diff --git a/.github/workflows/wiki.yml b/.github/workflows/wiki.yml
index 5816c9a7e9a..c5e92d52156 100644
--- a/.github/workflows/wiki.yml
+++ b/.github/workflows/wiki.yml
@@ -1,6 +1,7 @@
 name: Deploy to Wiki
 
 on:
+  workflow_dispatch:
   pull_request:
     paths:
       - 'wiki/**'
@@ -36,6 +37,8 @@ jobs:
           bazel run //scripts:wiki_table_of_contents_check -- ${GITHUB_WORKSPACE}
 
   wiki-deploy:
+    permissions:
+      contents: write
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
diff --git a/app/src/main/java/org/oppia/android/app/player/state/ImageRegionSelectionInteractionView.kt b/app/src/main/java/org/oppia/android/app/player/state/ImageRegionSelectionInteractionView.kt
index e7f2dbe3e2e..a113976602f 100644
--- a/app/src/main/java/org/oppia/android/app/player/state/ImageRegionSelectionInteractionView.kt
+++ b/app/src/main/java/org/oppia/android/app/player/state/ImageRegionSelectionInteractionView.kt
@@ -11,6 +11,7 @@ import androidx.fragment.app.FragmentManager
 import org.oppia.android.app.model.ImageWithRegions
 import org.oppia.android.app.model.UserAnswerState
 import org.oppia.android.app.shim.ViewBindingShim
+import org.oppia.android.app.translation.AppLanguageResourceHandler
 import org.oppia.android.app.utility.ClickableAreasImage
 import org.oppia.android.app.utility.OnClickableAreaClickedListener
 import org.oppia.android.app.view.ViewComponentFactory
@@ -46,6 +47,7 @@ class ImageRegionSelectionInteractionView @JvmOverloads constructor(
   @Inject lateinit var machineLocale: OppiaLocale.MachineLocale
   @Inject lateinit var accessibilityService: AccessibilityService
   @Inject lateinit var imageLoader: ImageLoader
+  @Inject lateinit var resourceHandler: AppLanguageResourceHandler
 
   private lateinit var entityId: String
   private lateinit var overlayView: FrameLayout
@@ -64,8 +66,8 @@ class ImageRegionSelectionInteractionView @JvmOverloads constructor(
     maybeInitializeClickableAreas()
   }
 
-  fun setUserAnswerState(userAnswerrState: UserAnswerState) {
-    this.userAnswerState = userAnswerrState
+  fun setUserAnswerState(userAnswerState: UserAnswerState) {
+    this.userAnswerState = userAnswerState
   }
 
   fun setEntityId(entityId: String) {
@@ -118,7 +120,8 @@ class ImageRegionSelectionInteractionView @JvmOverloads constructor(
       ::entityId.isInitialized &&
       ::imageUrl.isInitialized &&
       ::onRegionClicked.isInitialized &&
-      ::overlayView.isInitialized
+      ::overlayView.isInitialized &&
+      ::resourceHandler.isInitialized
     ) {
       loadImage()
 
@@ -129,7 +132,8 @@ class ImageRegionSelectionInteractionView @JvmOverloads constructor(
         bindingInterface,
         isAccessibilityEnabled = accessibilityService.isScreenReaderEnabled(),
         clickableAreas,
-        userAnswerState
+        userAnswerState,
+        resourceHandler
       )
       areasImage.addRegionViews()
       performAttachment(areasImage)
diff --git a/app/src/main/java/org/oppia/android/app/player/state/StatePlayerRecyclerViewAssembler.kt b/app/src/main/java/org/oppia/android/app/player/state/StatePlayerRecyclerViewAssembler.kt
index 8f1e627d77a..5126bd59028 100644
--- a/app/src/main/java/org/oppia/android/app/player/state/StatePlayerRecyclerViewAssembler.kt
+++ b/app/src/main/java/org/oppia/android/app/player/state/StatePlayerRecyclerViewAssembler.kt
@@ -1,5 +1,6 @@
 package org.oppia.android.app.player.state
 
+import android.app.Application
 import android.content.Context
 import android.view.LayoutInflater
 import android.view.View
@@ -91,7 +92,18 @@ import org.oppia.android.databinding.SubmittedHtmlAnswerItemBinding
 import org.oppia.android.databinding.TextInputInteractionItemBinding
 import org.oppia.android.domain.translation.TranslationController
 import org.oppia.android.util.accessibility.AccessibilityService
+import org.oppia.android.util.logging.ConsoleLogger
+import org.oppia.android.util.parser.html.CUSTOM_CONCEPT_CARD_TAG
+import org.oppia.android.util.parser.html.CUSTOM_IMG_TAG
+import org.oppia.android.util.parser.html.CUSTOM_LIST_LI_TAG
+import org.oppia.android.util.parser.html.CUSTOM_LIST_OL_TAG
+import org.oppia.android.util.parser.html.CUSTOM_LIST_UL_TAG
+import org.oppia.android.util.parser.html.CUSTOM_MATH_TAG
+import org.oppia.android.util.parser.html.ConceptCardTagHandler
 import org.oppia.android.util.parser.html.HtmlParser
+import org.oppia.android.util.parser.html.ImageTagHandler
+import org.oppia.android.util.parser.html.LiTagHandler
+import org.oppia.android.util.parser.html.MathTagHandler
 import org.oppia.android.util.threading.BackgroundDispatcher
 import javax.inject.Inject
 
@@ -145,7 +157,9 @@ class StatePlayerRecyclerViewAssembler private constructor(
   private val hasConversationView: Boolean,
   private val resourceHandler: AppLanguageResourceHandler,
   private val translationController: TranslationController,
-  private var userAnswerState: UserAnswerState
+  private var userAnswerState: UserAnswerState,
+  private val consoleLogger: ConsoleLogger,
+  private val conceptCardTagHandlerFactory: ConceptCardTagHandler.Factory,
 ) : HtmlParser.CustomOppiaTagActionListener {
   /**
    * A list of view models corresponding to past view models that are hidden by default. These are
@@ -180,6 +194,25 @@ class StatePlayerRecyclerViewAssembler private constructor(
     }
   }
 
+  private val displayLocale = resourceHandler.getDisplayLocale()
+  private val customTagHandlers = mapOf(
+    CUSTOM_LIST_LI_TAG to LiTagHandler(context, displayLocale),
+    CUSTOM_LIST_UL_TAG to LiTagHandler(context, displayLocale),
+    CUSTOM_LIST_OL_TAG to LiTagHandler(context, displayLocale),
+    CUSTOM_IMG_TAG to ImageTagHandler(consoleLogger),
+    CUSTOM_CONCEPT_CARD_TAG to ConceptCardTagHandler(
+      conceptCardTagHandlerFactory.createConceptCardLinkClickListener(),
+      consoleLogger
+    ),
+    // Pick an arbitrary line height since rendering doesn't actually happen.
+    CUSTOM_MATH_TAG to MathTagHandler(
+      consoleLogger,
+      context.assets,
+      10.0f,
+      false,
+      context.applicationContext as Application,
+    )
+  )
   private val isSplitView = ObservableField<Boolean>(false)
 
   override fun onConceptCardLinkClicked(view: View, skillId: String) {
@@ -350,7 +383,8 @@ class StatePlayerRecyclerViewAssembler private constructor(
         gcsEntityId,
         hasConversationView,
         isSplitView.get()!!,
-        playerFeatureSet.conceptCardSupport
+        playerFeatureSet.conceptCardSupport,
+        customTagHandlers
       )
     }
   }
@@ -913,7 +947,9 @@ class StatePlayerRecyclerViewAssembler private constructor(
     private val translationController: TranslationController,
     private val multiTypeBuilderFactory: BindableAdapter.MultiTypeBuilder.Factory,
     private val singleTypeBuilderFactory: BindableAdapter.SingleTypeBuilder.Factory,
-    private val userAnswerState: UserAnswerState
+    private val userAnswerState: UserAnswerState,
+    private val consoleLogger: ConsoleLogger,
+    private val conceptCardTagHandlerFactory: ConceptCardTagHandler.Factory,
   ) {
 
     private val adapterBuilder: BindableAdapter.MultiTypeBuilder<StateItemViewModel,
@@ -1400,7 +1436,9 @@ class StatePlayerRecyclerViewAssembler private constructor(
         hasConversationView,
         resourceHandler,
         translationController,
-        userAnswerState
+        userAnswerState,
+        consoleLogger,
+        conceptCardTagHandlerFactory
       )
       if (playerFeatureSet.conceptCardSupport) {
         customTagListener.proxyListener = assembler
@@ -1420,7 +1458,9 @@ class StatePlayerRecyclerViewAssembler private constructor(
       private val resourceHandler: AppLanguageResourceHandler,
       private val translationController: TranslationController,
       private val multiAdapterBuilderFactory: BindableAdapter.MultiTypeBuilder.Factory,
-      private val singleAdapterFactory: BindableAdapter.SingleTypeBuilder.Factory
+      private val singleAdapterFactory: BindableAdapter.SingleTypeBuilder.Factory,
+      private val consoleLogger: ConsoleLogger,
+      private val conceptCardTagHandlerFactory: ConceptCardTagHandler.Factory,
     ) {
       /**
        * Returns a new [Builder] for the specified GCS resource bucket information for loading
@@ -1446,7 +1486,9 @@ class StatePlayerRecyclerViewAssembler private constructor(
           translationController,
           multiAdapterBuilderFactory,
           singleAdapterFactory,
-          userAnswerState
+          userAnswerState,
+          consoleLogger,
+          conceptCardTagHandlerFactory
         )
       }
     }
diff --git a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/ContentViewModel.kt b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/ContentViewModel.kt
index 88c72d94734..c2a4dc26cce 100644
--- a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/ContentViewModel.kt
+++ b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/ContentViewModel.kt
@@ -1,7 +1,6 @@
 package org.oppia.android.app.player.state.itemviewmodel
 
-import android.text.Spannable
-import android.text.SpannableStringBuilder
+import org.oppia.android.util.parser.html.CustomHtmlContentHandler
 
 /** [StateItemViewModel] for content-card state. */
 class ContentViewModel(
@@ -9,30 +8,28 @@ class ContentViewModel(
   val gcsEntityId: String,
   val hasConversationView: Boolean,
   val isSplitView: Boolean,
-  val supportsConceptCards: Boolean
+  val supportsConceptCards: Boolean,
+  val customTagHandlers: Map<String, CustomHtmlContentHandler.CustomTagHandler>
 ) : StateItemViewModel(ViewType.CONTENT) {
 
   private val underscoreRegex = Regex("(?<=\\s|[,.;?!])_{3,}(?=\\s|[,.;?!])")
   private val replacementText = "Blank"
 
+  /** Returns content description by extracting text from [htmlContent]. */
+  fun getContentDescription(): String {
+    val contentDescription = CustomHtmlContentHandler.getContentDescription(
+      htmlContent.toString(),
+      imageRetriever = null,
+      customTagHandlers = customTagHandlers
+    )
+    return replaceRegexWithBlank(contentDescription)
+  }
+
   /**
    * Replaces "2+ underscores, with space/punctuation on both sides" in the input text with a
    * replacement string "blank", returning a Spannable.
    * Adjusts offsets to handle text length changes during replacements.
    */
-  fun replaceRegexWithBlank(inputText: CharSequence): Spannable {
-    val spannableStringBuilder = SpannableStringBuilder(inputText)
-    val matches = underscoreRegex.findAll(inputText)
-    var lengthOffset = 0
-
-    for (match in matches) {
-      val matchStart = match.range.first + lengthOffset
-      val matchEnd = match.range.last + 1 + lengthOffset
-      spannableStringBuilder.replace(matchStart, matchEnd, replacementText)
-
-      // Adjust offset due to change in length (difference between old and new text length)
-      lengthOffset += replacementText.length - (matchEnd - matchStart)
-    }
-    return spannableStringBuilder
-  }
+  private fun replaceRegexWithBlank(inputText: CharSequence): String =
+    underscoreRegex.replace(inputText, replacementText)
 }
diff --git a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionContentViewModel.kt b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionContentViewModel.kt
index 04fea533655..71eabdf43ea 100644
--- a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionContentViewModel.kt
+++ b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionContentViewModel.kt
@@ -2,7 +2,10 @@ package org.oppia.android.app.player.state.itemviewmodel
 
 import androidx.databinding.ObservableBoolean
 import org.oppia.android.app.model.SubtitledHtml
+import org.oppia.android.app.model.WrittenTranslationContext
 import org.oppia.android.app.viewmodel.ObservableViewModel
+import org.oppia.android.domain.translation.TranslationController
+import org.oppia.android.util.parser.html.CustomHtmlContentHandler
 
 /** [ObservableViewModel] for MultipleChoiceInput values or ItemSelectionInput values. */
 class SelectionInteractionContentViewModel(
@@ -10,10 +13,27 @@ class SelectionInteractionContentViewModel(
   val hasConversationView: Boolean,
   private val itemIndex: Int,
   private val selectionInteractionViewModel: SelectionInteractionViewModel,
-  val isEnabled: ObservableBoolean
+  val isEnabled: ObservableBoolean,
+  val customTagHandlers: Map<String, CustomHtmlContentHandler.CustomTagHandler>,
+  private val writtenTranslationContext: WrittenTranslationContext,
+  private val translationController: TranslationController,
 ) : ObservableViewModel() {
   var isAnswerSelected = ObservableBoolean()
 
+  /** Returns content description by extracting text from [htmlContent]. */
+  fun getContentDescription(): String {
+    val contentSubtitledHtml =
+      translationController.extractString(
+        htmlContent, writtenTranslationContext
+      )
+    return CustomHtmlContentHandler.getContentDescription(
+      contentSubtitledHtml,
+      imageRetriever = null,
+      customTagHandlers = customTagHandlers
+    )
+  }
+
+  /** Handles item click by updating the selection state based on user interaction. */
   fun handleItemClicked() {
     val isCurrentlySelected = isAnswerSelected.get()
     val shouldNowBeSelected =
diff --git a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionViewModel.kt b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionViewModel.kt
index d5f4b7016c7..a0604b8d326 100644
--- a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionViewModel.kt
+++ b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionViewModel.kt
@@ -22,6 +22,10 @@ import org.oppia.android.app.player.state.answerhandling.InteractionAnswerReceiv
 import org.oppia.android.app.translation.AppLanguageResourceHandler
 import org.oppia.android.app.viewmodel.ObservableArrayList
 import org.oppia.android.domain.translation.TranslationController
+import org.oppia.android.util.logging.ConsoleLogger
+import org.oppia.android.util.parser.html.CUSTOM_IMG_TAG
+import org.oppia.android.util.parser.html.CustomHtmlContentHandler
+import org.oppia.android.util.parser.html.ImageTagHandler
 import javax.inject.Inject
 
 /** Corresponds to the type of input that should be used for an item selection interaction view. */
@@ -52,7 +56,8 @@ class SelectionInteractionViewModel private constructor(
   val writtenTranslationContext: WrittenTranslationContext,
   private val translationController: TranslationController,
   private val resourceHandler: AppLanguageResourceHandler,
-  userAnswerState: UserAnswerState
+  userAnswerState: UserAnswerState,
+  consoleLogger: ConsoleLogger
 ) : StateItemViewModel(ViewType.SELECTION_INTERACTION), InteractionAnswerHandler {
   private val interactionId: String = interaction.id
 
@@ -81,9 +86,20 @@ class SelectionInteractionViewModel private constructor(
       ObservableBoolean(true)
     }
   }
-  val choiceItems: ObservableList<SelectionInteractionContentViewModel> =
-    computeChoiceItems(choiceSubtitledHtmls, hasConversationView, this, enabledItemsList)
+  private val customTagHandlers = mapOf<String, CustomHtmlContentHandler.CustomTagHandler>(
+    CUSTOM_IMG_TAG to ImageTagHandler(consoleLogger)
+  )
 
+  val choiceItems: ObservableList<SelectionInteractionContentViewModel> =
+    computeChoiceItems(
+      choiceSubtitledHtmls,
+      hasConversationView,
+      this,
+      enabledItemsList,
+      this@SelectionInteractionViewModel.writtenTranslationContext,
+      translationController,
+      customTagHandlers
+    )
   private var pendingAnswerError: String? = null
   private val isAnswerAvailable = ObservableField(false)
   val errorMessage = ObservableField<String>("")
@@ -287,7 +303,8 @@ class SelectionInteractionViewModel private constructor(
   /** Implementation of [StateItemViewModel.InteractionItemFactory] for this view model. */
   class FactoryImpl @Inject constructor(
     private val translationController: TranslationController,
-    private val resourceHandler: AppLanguageResourceHandler
+    private val resourceHandler: AppLanguageResourceHandler,
+    private val consoleLogger: ConsoleLogger
   ) : InteractionItemFactory {
     override fun create(
       entityId: String,
@@ -310,7 +327,8 @@ class SelectionInteractionViewModel private constructor(
         writtenTranslationContext,
         translationController,
         resourceHandler,
-        userAnswerState
+        userAnswerState,
+        consoleLogger
       )
     }
   }
@@ -320,7 +338,10 @@ class SelectionInteractionViewModel private constructor(
       choiceSubtitledHtmls: List<SubtitledHtml>,
       hasConversationView: Boolean,
       selectionInteractionViewModel: SelectionInteractionViewModel,
-      enabledItemsList: List<ObservableBoolean>
+      enabledItemsList: List<ObservableBoolean>,
+      writtenTranslationContext: WrittenTranslationContext,
+      translationController: TranslationController,
+      customTagHandlers: Map<String, CustomHtmlContentHandler.CustomTagHandler>
     ): ObservableArrayList<SelectionInteractionContentViewModel> {
       val observableList = ObservableArrayList<SelectionInteractionContentViewModel>()
       observableList += choiceSubtitledHtmls.mapIndexed { index, subtitledHtml ->
@@ -329,7 +350,10 @@ class SelectionInteractionViewModel private constructor(
           hasConversationView = hasConversationView,
           itemIndex = index,
           selectionInteractionViewModel = selectionInteractionViewModel,
-          isEnabled = enabledItemsList[index]
+          isEnabled = enabledItemsList[index],
+          customTagHandlers,
+          writtenTranslationContext,
+          translationController
         )
       }
       return observableList
diff --git a/app/src/main/java/org/oppia/android/app/utility/ClickableAreasImage.kt b/app/src/main/java/org/oppia/android/app/utility/ClickableAreasImage.kt
index fa77fa271de..dd57c27f29a 100644
--- a/app/src/main/java/org/oppia/android/app/utility/ClickableAreasImage.kt
+++ b/app/src/main/java/org/oppia/android/app/utility/ClickableAreasImage.kt
@@ -13,6 +13,7 @@ import org.oppia.android.app.model.ImageWithRegions.LabeledRegion
 import org.oppia.android.app.model.UserAnswerState
 import org.oppia.android.app.player.state.ImageRegionSelectionInteractionView
 import org.oppia.android.app.shim.ViewBindingShim
+import org.oppia.android.app.translation.AppLanguageResourceHandler
 import kotlin.math.roundToInt
 
 /** Helper class to handle clicks on an image along with highlighting the selected region. */
@@ -23,7 +24,8 @@ class ClickableAreasImage(
   bindingInterface: ViewBindingShim,
   private val isAccessibilityEnabled: Boolean,
   private val clickableAreas: List<LabeledRegion>,
-  userAnswerState: UserAnswerState
+  userAnswerState: UserAnswerState,
+  private val resourceHandler: AppLanguageResourceHandler
 ) {
   private var imageLabel: String? = null
   private val defaultRegionView by lazy { bindingInterface.getDefaultRegion(parentView) }
@@ -60,6 +62,16 @@ class ClickableAreasImage(
       // Remove any previously selected region excluding 0th index(image view)
       if (index > 0) {
         childView.setBackgroundResource(0)
+        if (childView.tag != null) {
+          val regionLabel = childView.tag as String
+          clickableAreas.find { it.label == regionLabel }?.let { clickableArea ->
+            updateRegionContentDescription(
+              childView,
+              clickableArea,
+              regionLabel == imageLabel
+            )
+          }
+        }
       }
     }
   }
@@ -112,8 +124,13 @@ class ClickableAreasImage(
       newView.isFocusable = true
       newView.isFocusableInTouchMode = true
       newView.tag = clickableArea.label
+
+      val isInitiallySelected = clickableArea.label.equals(imageLabel)
+      updateRegionContentDescription(newView, clickableArea, isInitiallySelected)
+
       newView.initializeToggleRegionTouchListener(clickableArea)
-      if (clickableArea.label.equals(imageLabel)) {
+
+      if (isInitiallySelected) {
         showOrHideRegion(newView = newView, clickableArea = clickableArea)
       }
       if (isAccessibilityEnabled) {
@@ -123,7 +140,7 @@ class ClickableAreasImage(
           showOrHideRegion(newView, clickableArea)
         }
       }
-      newView.contentDescription = clickableArea.contentDescription
+
       parentView.addView(newView)
     }
 
@@ -143,14 +160,18 @@ class ClickableAreasImage(
   }
 
   private fun showOrHideRegion(newView: View, clickableArea: LabeledRegion) {
-    resetRegionSelectionViews()
-    listener.onClickableAreaTouched(
-      NamedRegionClickedEvent(
-        clickableArea.label,
-        clickableArea.contentDescription
+    if (clickableArea.label != imageLabel) {
+      imageLabel = clickableArea.label
+      resetRegionSelectionViews()
+      newView.setBackgroundResource(R.drawable.selected_region_background)
+
+      listener.onClickableAreaTouched(
+        NamedRegionClickedEvent(
+          clickableArea.label,
+          generateContentDescription(clickableArea, true)
+        )
       )
-    )
-    newView.setBackgroundResource(R.drawable.selected_region_background)
+    }
   }
 
   private fun View.initializeShowRegionTouchListener() {
@@ -172,4 +193,27 @@ class ClickableAreasImage(
       return@setOnTouchListener true
     }
   }
+
+  private fun generateContentDescription(
+    clickableArea: LabeledRegion,
+    isSelected: Boolean
+  ): String = if (isSelected) {
+    resourceHandler.getStringInLocaleWithWrapping(
+      R.string.selected_image_region_selection_content_description,
+      clickableArea.label
+    )
+  } else {
+    resourceHandler.getStringInLocaleWithWrapping(
+      R.string.unselected_image_region_selection_content_description,
+      clickableArea.label
+    )
+  }
+
+  private fun updateRegionContentDescription(
+    view: View,
+    clickableArea: LabeledRegion,
+    isSelected: Boolean
+  ) {
+    view.contentDescription = generateContentDescription(clickableArea, isSelected)
+  }
 }
diff --git a/app/src/main/res/layout/content_item.xml b/app/src/main/res/layout/content_item.xml
index a29a44814fe..192d0a42642 100644
--- a/app/src/main/res/layout/content_item.xml
+++ b/app/src/main/res/layout/content_item.xml
@@ -50,7 +50,7 @@
       android:minWidth="48dp"
       android:minHeight="48dp"
       android:text="@{htmlContent}"
-      android:contentDescription="@{viewModel.replaceRegexWithBlank(htmlContent)}"
+      android:contentDescription="@{viewModel.getContentDescription()}"
       android:textColor="@color/component_color_shared_primary_text_color"
       android:textColorLink="@color/component_color_shared_link_text_color"
       android:textSize="16sp"
diff --git a/app/src/main/res/layout/item_selection_interaction_items.xml b/app/src/main/res/layout/item_selection_interaction_items.xml
index 7fe2e6a5ba5..c7537f23e0e 100755
--- a/app/src/main/res/layout/item_selection_interaction_items.xml
+++ b/app/src/main/res/layout/item_selection_interaction_items.xml
@@ -43,6 +43,7 @@
       android:layout_toEndOf="@+id/item_selection_checkbox"
       android:fontFamily="sans-serif"
       android:text="@{htmlContent}"
+      android:contentDescription="@{viewModel.getContentDescription()}"
       android:textColor="@{viewModel.isEnabled ? @color/component_color_shared_item_selection_interaction_enabled_color : @color/component_color_shared_item_selection_interaction_disabled_color}"
       android:textSize="16sp" />
   </RelativeLayout>
diff --git a/app/src/main/res/layout/multiple_choice_interaction_items.xml b/app/src/main/res/layout/multiple_choice_interaction_items.xml
index dcbf7239e1f..997f88601e3 100755
--- a/app/src/main/res/layout/multiple_choice_interaction_items.xml
+++ b/app/src/main/res/layout/multiple_choice_interaction_items.xml
@@ -43,6 +43,7 @@
       android:layout_toEndOf="@+id/multiple_choice_radio_button"
       android:fontFamily="sans-serif"
       android:text="@{htmlContent}"
+      android:contentDescription="@{viewModel.getContentDescription()}"
       android:textColor="@{viewModel.isAnswerSelected() ? @color/component_color_shared_selection_interaction_selected_text_color : @color/component_color_shared_selection_interaction_unselected_text_color}"
       android:textSize="16sp" />
   </RelativeLayout>
diff --git a/app/src/main/res/values-ar/strings.xml b/app/src/main/res/values-ar/strings.xml
index fe5f53dd75e..5f928cf9c0f 100644
--- a/app/src/main/res/values-ar/strings.xml
+++ b/app/src/main/res/values-ar/strings.xml
@@ -39,7 +39,7 @@
   <string name="concept_card_toolbar_title">بطاقة المفهوم</string>
   <string name="concept_card_one_button_text">بطاقة المفاهيم 1</string>
   <string name="concept_card_two_button_text">بطاقة المفاهيم 2</string>
-  <string name="revision_card_toolbar_title">بطاقة المراجعة</string>
+  <string name="revision_card_toolbar_title">دليل الدراسة</string>
   <string name="unsaved_exploration_dialog_title">هل تريد المغادرة إلى صفحة الموضوع؟</string>
   <string name="unsaved_exploration_dialog_description">لن يتم حفظ تقدمك.</string>
   <string name="unsaved_exploration_dialog_leave_button">مغادرة</string>
@@ -90,9 +90,9 @@
   <string name="onboarding_activity_title">مقدمة</string>
   <string name="frequently_asked_questions_FAQ">الأسئلة الأكثر تكرارا</string>
   <string name="info">معلومات</string>
-  <string name="lessons">الدروس</string>
+  <string name="learn">تعلم</string>
   <string name="practice">ممارسة</string>
-  <string name="revision">مراجعة</string>
+  <string name="study">يذاكر</string>
   <string name="administrator_controls_title">أدوات تحكم المشرف</string>
   <string name="topic_page">صفحة الموضوع</string>
   <string name="topic_name">الموضوع: %s</string>
diff --git a/app/src/main/res/values-pcm-rNG/strings.xml b/app/src/main/res/values-pcm-rNG/strings.xml
index 0774dae0c11..2271b7f790f 100644
--- a/app/src/main/res/values-pcm-rNG/strings.xml
+++ b/app/src/main/res/values-pcm-rNG/strings.xml
@@ -36,7 +36,7 @@
   <string name="concept_card_toolbar_title">Concept Card</string>
   <string name="concept_card_one_button_text">Concept Card 1</string>
   <string name="concept_card_two_button_text">Concept Card 2</string>
-  <string name="revision_card_toolbar_title">Revision Card</string>
+  <string name="revision_card_toolbar_title" fuzzy="true">Revision Card</string>
   <string name="unsaved_exploration_dialog_title">Comot go the topic page?</string>
   <string name="unsaved_exploration_dialog_description">Wetin you don do before no go save</string>
   <string name="unsaved_exploration_dialog_leave_button">Comot</string>
@@ -86,9 +86,7 @@
   <string name="onboarding_activity_title">Introduction</string>
   <string name="frequently_asked_questions_FAQ">Frequently Asked Questions (FAQs)</string>
   <string name="info">Info</string>
-  <string name="lessons">Lessons</string>
   <string name="practice">Practice</string>
-  <string name="revision">Revision</string>
   <string name="administrator_controls_title">Administrator Controls</string>
   <string name="topic_page">Topic page</string>
   <string name="topic_name">Topic: %s</string>
diff --git a/app/src/main/res/values-pt-rBR/strings.xml b/app/src/main/res/values-pt-rBR/strings.xml
index 63042bc8413..98e6088fff3 100644
--- a/app/src/main/res/values-pt-rBR/strings.xml
+++ b/app/src/main/res/values-pt-rBR/strings.xml
@@ -45,7 +45,7 @@
   <string name="concept_card_toolbar_title">Cartão de Conceito</string>
   <string name="concept_card_one_button_text">Cartão Conceitual 1</string>
   <string name="concept_card_two_button_text">Cartão Conceitual 2</string>
-  <string name="revision_card_toolbar_title">Cartão de Revisão</string>
+  <string name="revision_card_toolbar_title" fuzzy="true">Cartão de Revisão</string>
   <string name="unsaved_exploration_dialog_title">Pretende ir para a página do tópico?</string>
   <string name="unsaved_exploration_dialog_description">Seu progresso não será salvo.</string>
   <string name="unsaved_exploration_dialog_leave_button">Sair</string>
@@ -96,9 +96,7 @@
   <string name="onboarding_activity_title">Introdução</string>
   <string name="frequently_asked_questions_FAQ">Perguntas Frequentes (FAQs)</string>
   <string name="info">Info</string>
-  <string name="lessons">Lições</string>
   <string name="practice">Prática</string>
-  <string name="revision">Revisão</string>
   <string name="administrator_controls_title">Controles do administrador</string>
   <string name="topic_page">Página do tópico</string>
   <string name="topic_name">Tópico: %s</string>
diff --git a/app/src/main/res/values-sw/strings.xml b/app/src/main/res/values-sw/strings.xml
index f827cae27ef..4ec916e993c 100644
--- a/app/src/main/res/values-sw/strings.xml
+++ b/app/src/main/res/values-sw/strings.xml
@@ -31,7 +31,7 @@
   <string name="cellular_data_alert_dialog_description">Kutiririsha sauti kunaweza kutumia data nyingi ya mtandao wa simu.</string>
   <string name="cellular_data_alert_dialog_checkbox">Usionyeshe ujumbe huu tena</string>
   <string name="concept_card_toolbar_title">Kadi ya Dhana</string>
-  <string name="revision_card_toolbar_title">Kadi ya Marudio</string>
+  <string name="revision_card_toolbar_title" fuzzy="true">Kadi ya Marudio</string>
   <string name="unsaved_exploration_dialog_title">Je, ungependa kwenda kwenye Ukurasa wa Mada?</string>
   <string name="unsaved_exploration_dialog_description">Maendeleo yako hayatahifadhiwa.</string>
   <string name="unsaved_exploration_dialog_leave_button">Toka</string>
@@ -69,9 +69,7 @@
   <string name="onboarding_activity_title">Utangulizi</string>
   <string name="frequently_asked_questions_FAQ">maswali yanayoulizwa mara kwa mara</string>
   <string name="info">habari</string>
-  <string name="lessons">Masomo</string>
   <string name="practice">Mazoezi</string>
-  <string name="revision">Mazoezi</string>
   <string name="administrator_controls_title">Vidhibiti vya Msimamizi</string>
   <string name="topic_page">Ukurasa wa mada</string>
   <string name="topic_name">mada: %s</string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 4d6299de34d..4eb884b7ab1 100755
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -191,6 +191,8 @@
   <string name="correct">Correct!</string>
   <string name="topic_prefix">Topic: %s</string>
   <string name="welcome_profile_name">%1$s %2$s!</string>
+  <string name="selected_image_region_selection_content_description">Image showing %1$s.</string>
+  <string name="unselected_image_region_selection_content_description">Select %1$s image.</string>
   <plurals name="chapter_count">
     <item quantity="one">1 Chapter</item>
     <item quantity="other">%s Chapters</item>
diff --git a/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt b/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt
index 5f436a48dc7..50003cdc606 100644
--- a/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt
+++ b/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt
@@ -5230,16 +5230,80 @@ class StateFragmentTest {
       playThroughRatioExplorationState13()
       playThroughRatioExplorationState14()
 
-      val expectedDescription = "James turned the page, and saw a recipe for banana smoothie." +
-        " Yummy!\n\n2 cups of milk and 1 cup of banana puree \n\n“I can make this,” he said." +
-        " “We’ll need to mix milk and banana puree in the ratio Blank.”\n\nCan you complete" +
-        " James’s sentence? What is the ratio of milk to banana puree?”"
+      val expectedDescription = "James turned the page, and saw a recipe for banana smoothie. " +
+        "Yummy!\nImage illustrating 2 cups of milk and 1 cup of banana puree\n“I can make this," +
+        "” he said. “We’ll need to mix milk and banana puree in the ratio Blank.”\nCan you " +
+        "complete James’s sentence? What is the ratio of milk to banana puree?”"
 
       onView(withId(R.id.content_text_view))
         .check(matches(withContentDescription(expectedDescription)))
     }
   }
 
+  @Test
+  fun testStateFragment_contentDescription_itemSelectionInteraction() {
+    setUpTestWithLanguageSwitchingFeatureOff()
+    launchForExploration(TEST_EXPLORATION_ID_2, shouldSavePartialProgress = false).use {
+      startPlayingExploration()
+      playThroughPrototypeState1()
+      playThroughPrototypeState2()
+      playThroughPrototypeState3()
+      playThroughPrototypeState4()
+      verifyViewTypeIsPresent(SELECTION_INTERACTION)
+
+      onView(
+        atPositionOnView(
+          recyclerViewId = R.id.selection_interaction_recyclerview,
+          position = 2,
+          targetViewId = R.id.item_selection_contents_text_view
+        )
+      ).check(matches(withContentDescription("Green")))
+
+      onView(
+        atPositionOnView(
+          recyclerViewId = R.id.selection_interaction_recyclerview,
+          position = 3,
+          targetViewId = R.id.item_selection_contents_text_view
+        )
+      ).check(matches(withContentDescription("Blue")))
+    }
+  }
+
+  @Test
+  fun testStateFragment_contentDescription_multipleChoiceInteraction() {
+    setUpTestWithLanguageSwitchingFeatureOff()
+    launchForExploration(RATIOS_EXPLORATION_ID_0, shouldSavePartialProgress = false).use {
+      startPlayingExploration()
+
+      playThroughRatioExplorationState1()
+      playThroughRatioExplorationState2()
+      playThroughRatioExplorationState3()
+      playThroughRatioExplorationState4()
+      playThroughRatioExplorationState5()
+      playThroughRatioExplorationState6()
+      playThroughRatioExplorationState7()
+      playThroughRatioExplorationState8()
+      playThroughRatioExplorationState9()
+      playThroughRatioExplorationState10()
+      playThroughRatioExplorationState11()
+      playThroughRatioExplorationState12()
+      playThroughRatioExplorationState13()
+      playThroughRatioExplorationState14()
+      playThroughRatioExplorationState15()
+
+      val expectedDescription = "Image illustrating On the left, there is 1-unit wide glass " +
+        "filled with apple puree. On the right, there is 2-unit wide glass filled with milk."
+
+      onView(
+        atPositionOnView(
+          recyclerViewId = R.id.selection_interaction_recyclerview,
+          position = 2,
+          targetViewId = R.id.multiple_choice_content_text_view
+        )
+      ).check(matches(withContentDescription(expectedDescription)))
+    }
+  }
+
   @Test
   fun testFragment_argumentsAreCorrect() {
     setUpTestWithLanguageSwitchingFeatureOff()
@@ -5345,6 +5409,12 @@ class StateFragmentTest {
     clickContinueNavigationButton()
   }
 
+  private fun playThroughRatioExplorationState15() {
+    typeTextInput("2:1")
+    clickSubmitAnswerButton()
+    clickContinueNavigationButton()
+  }
+
   private fun addShadowMediaPlayerException(dataSource: Any, exception: Exception) {
     val classLoader = StateFragmentTest::class.java.classLoader!!
     val shadowMediaPlayerClass = classLoader.loadClass("org.robolectric.shadows.ShadowMediaPlayer")
diff --git a/app/src/sharedTest/java/org/oppia/android/app/testing/ImageRegionSelectionInteractionViewTest.kt b/app/src/sharedTest/java/org/oppia/android/app/testing/ImageRegionSelectionInteractionViewTest.kt
index 6b558212760..9690ec629d4 100644
--- a/app/src/sharedTest/java/org/oppia/android/app/testing/ImageRegionSelectionInteractionViewTest.kt
+++ b/app/src/sharedTest/java/org/oppia/android/app/testing/ImageRegionSelectionInteractionViewTest.kt
@@ -11,6 +11,7 @@ import androidx.test.espresso.action.ViewActions.click
 import androidx.test.espresso.assertion.ViewAssertions.matches
 import androidx.test.espresso.matcher.ViewMatchers.isDisplayed
 import androidx.test.espresso.matcher.ViewMatchers.isEnabled
+import androidx.test.espresso.matcher.ViewMatchers.withContentDescription
 import androidx.test.espresso.matcher.ViewMatchers.withId
 import androidx.test.espresso.matcher.ViewMatchers.withTagValue
 import androidx.test.espresso.matcher.ViewMatchers.withText
@@ -177,7 +178,7 @@ class ImageRegionSelectionInteractionViewTest {
       assertThat(regionClickedEvent.value)
         .isEqualTo(
           NamedRegionClickedEvent(
-            regionLabel = "Region 3", contentDescription = "You have selected Region 3"
+            regionLabel = "Region 3", contentDescription = "Image showing Region 3."
           )
         )
     }
@@ -218,12 +219,26 @@ class ImageRegionSelectionInteractionViewTest {
       assertThat(regionClickedEvent.value)
         .isEqualTo(
           NamedRegionClickedEvent(
-            regionLabel = "Region 2", contentDescription = "You have selected Region 2"
+            regionLabel = "Region 2", contentDescription = "Image showing Region 2."
           )
         )
     }
   }
 
+  @Test
+  // TODO(#1611): Fix ImageRegionSelectionInteractionViewTest
+  @RunOn(TestPlatform.ESPRESSO)
+  fun testImageRegionSelectionInteractionView_initialContentDescriptionRegion3_isCorrect() {
+    launch(ImageRegionSelectionTestActivity::class.java).use {
+      onView(
+        allOf(
+          withTagValue(`is`("Region 3")),
+          withContentDescription("Select Region 3 image.")
+        )
+      ).check(matches(isDisplayed()))
+    }
+  }
+
   @Test
   // TODO(#1611): Fix ImageRegionSelectionInteractionViewTest
   @RunOn(TestPlatform.ESPRESSO)
@@ -280,7 +295,7 @@ class ImageRegionSelectionInteractionViewTest {
       assertThat(regionClickedEvent.value)
         .isEqualTo(
           NamedRegionClickedEvent(
-            regionLabel = "Region 2", contentDescription = "You have selected Region 2"
+            regionLabel = "Region 2", contentDescription = "Image showing Region 2."
           )
         )
     }
@@ -308,7 +323,7 @@ class ImageRegionSelectionInteractionViewTest {
       assertThat(regionClickedEvent.value)
         .isEqualTo(
           NamedRegionClickedEvent(
-            regionLabel = "Region 3", contentDescription = "You have selected Region 3"
+            regionLabel = "Region 3", contentDescription = "Image showing Region 3."
           )
         )
     }
@@ -352,7 +367,7 @@ class ImageRegionSelectionInteractionViewTest {
       assertThat(regionClickedEvent.value)
         .isEqualTo(
           NamedRegionClickedEvent(
-            regionLabel = "Region 3", contentDescription = "You have selected Region 3"
+            regionLabel = "Region 3", contentDescription = "Image showing Region 3."
           )
         )
     }
@@ -394,7 +409,7 @@ class ImageRegionSelectionInteractionViewTest {
       assertThat(regionClickedEvent.value)
         .isEqualTo(
           NamedRegionClickedEvent(
-            regionLabel = "Region 2", contentDescription = "You have selected Region 2"
+            regionLabel = "Region 2", contentDescription = "Image showing Region 2."
           )
         )
     }
diff --git a/scripts/assets/test_file_exemptions.textproto b/scripts/assets/test_file_exemptions.textproto
index 0af71967b95..2b4731054d5 100644
--- a/scripts/assets/test_file_exemptions.textproto
+++ b/scripts/assets/test_file_exemptions.textproto
@@ -4102,10 +4102,6 @@ test_file_exemption {
   exempted_file_path: "testing/src/main/java/org/oppia/android/testing/math/ComparableOperationSubject.kt"
   test_file_not_required: true
 }
-test_file_exemption {
-  exempted_file_path: "testing/src/main/java/org/oppia/android/testing/math/TokenSubject.kt"
-  test_file_not_required: true
-}
 test_file_exemption {
   exempted_file_path: "testing/src/main/java/org/oppia/android/testing/mockito/MockitoKotlinHelper.kt"
   test_file_not_required: true
diff --git a/testing/src/main/java/org/oppia/android/testing/math/TokenSubject.kt b/testing/src/main/java/org/oppia/android/testing/math/TokenSubject.kt
index 737de61a7b9..49cce0f2030 100644
--- a/testing/src/main/java/org/oppia/android/testing/math/TokenSubject.kt
+++ b/testing/src/main/java/org/oppia/android/testing/math/TokenSubject.kt
@@ -26,8 +26,6 @@ import org.oppia.android.util.math.MathTokenizer.Companion.Token.RightParenthesi
 import org.oppia.android.util.math.MathTokenizer.Companion.Token.SquareRootSymbol
 import org.oppia.android.util.math.MathTokenizer.Companion.Token.VariableName
 
-// TODO(#4121): Add tests for this class.
-
 /**
  * Truth subject for verifying properties of [Token]s.
  *
diff --git a/testing/src/test/java/org/oppia/android/testing/math/BUILD.bazel b/testing/src/test/java/org/oppia/android/testing/math/BUILD.bazel
index efa01a88b38..cdc91cd8b0f 100644
--- a/testing/src/test/java/org/oppia/android/testing/math/BUILD.bazel
+++ b/testing/src/test/java/org/oppia/android/testing/math/BUILD.bazel
@@ -83,6 +83,20 @@ oppia_android_test(
     ],
 )
 
+oppia_android_test(
+    name = "TokenSubjectTest",
+    srcs = ["TokenSubjectTest.kt"],
+    custom_package = "org.oppia.android.testing.math",
+    test_class = "org.oppia.android.testing.math.TokenSubjectTest",
+    test_manifest = "//testing:test_manifest",
+    deps = [
+        "//testing/src/main/java/org/oppia/android/testing/math:token_subject",
+        "//third_party:com_google_truth_truth",
+        "//third_party:junit_junit",
+        "//third_party:robolectric_android-all",
+    ],
+)
+
 oppia_android_test(
     name = "MathParsingErrorSubjectTest",
     srcs = ["MathParsingErrorSubjectTest.kt"],
diff --git a/testing/src/test/java/org/oppia/android/testing/math/TokenSubjectTest.kt b/testing/src/test/java/org/oppia/android/testing/math/TokenSubjectTest.kt
new file mode 100644
index 00000000000..a50967aa57d
--- /dev/null
+++ b/testing/src/test/java/org/oppia/android/testing/math/TokenSubjectTest.kt
@@ -0,0 +1,217 @@
+package org.oppia.android.testing.math
+
+import org.junit.Assert.assertThrows
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+import org.oppia.android.util.math.MathTokenizer.Companion.Token
+
+/** Tests for [TokenSubject]. */
+@RunWith(JUnit4::class)
+class TokenSubjectTest {
+
+  @Test
+  fun testTokenSubject_passesWithCorrectStartIndex() {
+    val token = Token.PositiveInteger(42, 10, 15)
+    TokenSubject.assertThat(token).hasStartIndexThat().isEqualTo(10)
+  }
+
+  @Test
+  fun testTokenSubject_failsWithIncorrectStartIndex() {
+    val token = Token.PositiveInteger(42, 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token).hasStartIndexThat().isEqualTo(11)
+    }
+  }
+
+  @Test
+  fun testTokenSubject_passesWithCorrectEndIndex() {
+    val token = Token.PositiveInteger(42, 10, 15)
+    TokenSubject.assertThat(token).hasEndIndexThat().isEqualTo(15)
+  }
+
+  @Test
+  fun testTokenSubject_failsWithIncorrectEndIndex() {
+    val token = Token.PositiveInteger(42, 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token).hasEndIndexThat().isEqualTo(14)
+    }
+  }
+
+  @Test
+  fun testTokenSubject_passesWithCorrectPositiveIntegerValue() {
+    val token = Token.PositiveInteger(42, 10, 15)
+    TokenSubject.assertThat(token).isPositiveIntegerWhoseValue().isEqualTo(42)
+  }
+
+  @Test
+  fun testTokenSubject_failsWithIncorrectPositiveIntegerValue() {
+    val token = Token.PositiveInteger(42, 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token).isPositiveIntegerWhoseValue().isEqualTo(45)
+    }
+  }
+
+  @Test
+  fun testTokenSubject_passesWithCoreectPositiveRealNumberValue() {
+    val token = Token.PositiveRealNumber(3.14, 10, 15)
+    TokenSubject.assertThat(token).isPositiveRealNumberWhoseValue().isEqualTo(3.14)
+  }
+
+  fun testTokenSubject_failsWithIncorrectPositiveRealNumberValue() {
+    val token = Token.PositiveRealNumber(3.14, 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token).isPositiveRealNumberWhoseValue().isEqualTo(25)
+    }
+  }
+
+  @Test
+  fun testTokenSubject_passesWithCorrectVariableName() {
+    val token = Token.VariableName("x", 10, 15)
+    TokenSubject.assertThat(token).isVariableWhoseName().isEqualTo("x")
+  }
+
+  @Test
+  fun testTokenSubject_isVariableWhoseName_incorrectName_fails() {
+    val token = Token.VariableName("x", 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token).isVariableWhoseName().isEqualTo("y")
+    }
+  }
+
+  @Test
+  fun testTokenSubject_passesWithCorrectFunctionNameAndAllowedStatus() {
+    val token = Token.FunctionName("sqrt", true, 10, 15)
+    TokenSubject.assertThat(token)
+      .isFunctionNameThat()
+      .hasNameThat().isEqualTo("sqrt")
+  }
+
+  @Test
+  fun testTokenSubject_failsWithIncorrectFunctionNameAndAllowedStatus() {
+    val token = Token.FunctionName("sqrt", true, 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token)
+        .isFunctionNameThat()
+        .hasNameThat().isEqualTo("sine")
+    }
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsMinusSymbol() {
+    val token = Token.MinusSymbol(10, 11)
+    TokenSubject.assertThat(token).isMinusSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsSquareRootSymbol() {
+    val token = Token.SquareRootSymbol(10, 11)
+    TokenSubject.assertThat(token).isSquareRootSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsPlusSymbol() {
+    val token = Token.PlusSymbol(10, 11)
+    TokenSubject.assertThat(token).isPlusSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsMultiplySymbol() {
+    val token = Token.MultiplySymbol(10, 11)
+    TokenSubject.assertThat(token).isMultiplySymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsDivideSymbol() {
+    val token = Token.DivideSymbol(10, 11)
+    TokenSubject.assertThat(token).isDivideSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsExponentiationSymbol() {
+    val token = Token.ExponentiationSymbol(10, 11)
+    TokenSubject.assertThat(token).isExponentiationSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsEqualsSymbol() {
+    val token = Token.EqualsSymbol(10, 11)
+    TokenSubject.assertThat(token).isEqualsSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsLeftParenthesisSymbol() {
+    val token = Token.LeftParenthesisSymbol(10, 11)
+    TokenSubject.assertThat(token).isLeftParenthesisSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_symbolIsRightParenthesisSymbol() {
+    val token = Token.RightParenthesisSymbol(10, 11)
+    TokenSubject.assertThat(token).isRightParenthesisSymbol()
+  }
+
+  @Test
+  fun testTokenSubject_failsWithIncorrectSymbol() {
+    val token = Token.RightParenthesisSymbol(10, 11)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token).isMinusSymbol()
+    }
+  }
+
+  @Test
+  fun testTokenSubject_checkIsInvalidToken_passes() {
+    val token = Token.InvalidToken(10, 11)
+    TokenSubject.assertThat(token).isInvalidToken()
+  }
+
+  @Test
+  fun testTokenSubject_checkIsInvalidToken_fails() {
+    val token = Token.PositiveInteger(10, 11, 42)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token).isInvalidToken()
+    }
+  }
+
+  @Test
+  fun testTokenSubject_checkIsIncompleteFunctionName() {
+    val token = Token.IncompleteFunctionName(10, 11)
+    TokenSubject.assertThat(token).isIncompleteFunctionName()
+  }
+
+  @Test
+  fun testTokenSubject_functionNameSubject_nameCheck_passes() {
+    val token = Token.FunctionName("sqrt", true, 10, 15)
+    TokenSubject.assertThat(token)
+      .isFunctionNameThat()
+      .hasNameThat().isEqualTo("sqrt")
+  }
+
+  @Test
+  fun testTokenSubject_functionNameSubject_nameCheck_fails() {
+    val token = Token.FunctionName("sqrt", true, 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token)
+        .isFunctionNameThat()
+        .hasNameThat().isEqualTo("sin")
+    }
+  }
+
+  @Test
+  fun testTokenSubject_functionNameSubject_allowedPropertyCheck_passes() {
+    val token = Token.FunctionName("sqrt", true, 10, 15)
+    TokenSubject.assertThat(token)
+      .isFunctionNameThat()
+      .hasIsAllowedPropertyThat().isTrue()
+  }
+
+  @Test
+  fun testTokenSubject_functionNameSubject_allowedPropertyCheck_fails() {
+    val token = Token.FunctionName("sqrt", false, 10, 15)
+    assertThrows(AssertionError::class.java) {
+      TokenSubject.assertThat(token)
+        .isFunctionNameThat()
+        .hasIsAllowedPropertyThat().isTrue()
+    }
+  }
+}
diff --git a/utility/src/main/java/org/oppia/android/util/parser/html/CustomHtmlContentHandler.kt b/utility/src/main/java/org/oppia/android/util/parser/html/CustomHtmlContentHandler.kt
index 25cc7bf29d3..0e9988be8b4 100644
--- a/utility/src/main/java/org/oppia/android/util/parser/html/CustomHtmlContentHandler.kt
+++ b/utility/src/main/java/org/oppia/android/util/parser/html/CustomHtmlContentHandler.kt
@@ -28,12 +28,14 @@ class CustomHtmlContentHandler private constructor(
   private val contentDescriptionBuilder = StringBuilder()
   private val tagContentDescriptions = mutableMapOf<Int, String>()
   private var isInListItem = false
-  private var pendingNewline = false
   private val blockTags = setOf("p", "ol", "ul", "li", "oppia-ul", "oppia-ol", "oppia-li", "div")
+  // Indicates if a newline should be added before the next text content for block elements.
+  private var pendingNewline = false
 
   override fun endElement(uri: String?, localName: String?, qName: String?) {
     originalContentHandler?.endElement(uri, localName, qName)
-    if (localName in blockTags) {
+    val tagName = qName ?: localName
+    if (tagName in blockTags) {
       isInListItem = false
     }
     currentTrackedTag = null
@@ -57,7 +59,7 @@ class CustomHtmlContentHandler private constructor(
       contentDescriptionBuilder.append('\n')
       pendingNewline = false
     }
-    ch?.let { contentDescriptionBuilder.append(String(it, start, length)) }
+    ch?.let { contentDescriptionBuilder.appendRange(it, start, start + length) }
   }
 
   override fun endDocument() {
@@ -69,10 +71,17 @@ class CustomHtmlContentHandler private constructor(
     // Defer custom tag management to the tag handler so that Android's element parsing takes
     // precedence.
     currentTrackedTag = TrackedTag(checkNotNull(localName), checkNotNull(atts))
-    if (localName in blockTags) {
+    val tagName = qName ?: localName
+    if (tagName in blockTags) {
       pendingNewline = true
       isInListItem = true
     }
+    if (tagName == "a") {
+      val href = atts.getValue("href")
+      if (href != null) {
+        tagContentDescriptions[contentDescriptionBuilder.length] = "$href "
+      }
+    }
     originalContentHandler?.startElement(uri, localName, qName, atts)
   }
 
@@ -148,6 +157,7 @@ class CustomHtmlContentHandler private constructor(
     val attributes: Attributes,
     val openTagIndex: Int
   )
+
   /**
    * Returns the complete content description for the processed HTML, including descriptions
    * from all custom tags.
@@ -156,11 +166,16 @@ class CustomHtmlContentHandler private constructor(
     val rawDesc = buildString {
       var lastIndex = 0
       tagContentDescriptions.entries.sortedBy { it.key }.forEach { (index, description) ->
-        if (index > lastIndex) {
-          append(contentDescriptionBuilder.substring(lastIndex, index))
+        if (index > lastIndex && index <= contentDescriptionBuilder.length) {
+          append(
+            contentDescriptionBuilder.substring(
+              lastIndex,
+              minOf(index, contentDescriptionBuilder.length)
+            )
+          )
         }
         append(description)
-        lastIndex = index
+        lastIndex = minOf(index, contentDescriptionBuilder.length)
       }
       if (lastIndex < contentDescriptionBuilder.length) {
         append(contentDescriptionBuilder.substring(lastIndex))
@@ -168,6 +183,7 @@ class CustomHtmlContentHandler private constructor(
     }
     return rawDesc.replace(Regex("\n+"), "\n").trim()
   }
+
   /** Handler interface for a custom tag and its attributes. */
   interface CustomTagHandler {
     /**
@@ -259,6 +275,9 @@ class CustomHtmlContentHandler private constructor(
       customTagHandlers: Map<String, CustomTagHandler>
     ): String where T : Html.ImageGetter, T : ImageRetriever {
       val handler = CustomHtmlContentHandler(customTagHandlers, imageRetriever)
+
+      // Triggers the HTML parsing process, allowing CustomHtmlContentHandler to
+      // intercept and populate the contentDescriptionBuilder.
       HtmlCompat.fromHtml(
         "<init-custom-handler/>$html",
         HtmlCompat.FROM_HTML_MODE_LEGACY,
@@ -267,6 +286,7 @@ class CustomHtmlContentHandler private constructor(
       )
       return handler.getContentDescription()
     }
+
     /**
      * Returns a new [Spannable] with HTML parsed from [html] using the specified [imageRetriever]
      * for handling image retrieval, and map of tags to [CustomTagHandler]s for handling custom
diff --git a/utility/src/main/java/org/oppia/android/util/parser/html/LiTagHandler.kt b/utility/src/main/java/org/oppia/android/util/parser/html/LiTagHandler.kt
index 28321115984..239979e9878 100644
--- a/utility/src/main/java/org/oppia/android/util/parser/html/LiTagHandler.kt
+++ b/utility/src/main/java/org/oppia/android/util/parser/html/LiTagHandler.kt
@@ -9,7 +9,6 @@ import android.text.Spanned
 import android.text.style.ImageSpan
 import androidx.core.view.ViewCompat
 import org.oppia.android.util.locale.OppiaLocale
-import org.xml.sax.Attributes
 import java.util.Stack
 
 /** The custom <li> tag corresponding to [LiTagHandler]. */
@@ -28,7 +27,7 @@ const val CUSTOM_LIST_OL_TAG = "oppia-ol"
 class LiTagHandler(
   private val context: Context,
   private val displayLocale: OppiaLocale.DisplayLocale
-) : CustomHtmlContentHandler.CustomTagHandler, CustomHtmlContentHandler.ContentDescriptionProvider {
+) : CustomHtmlContentHandler.CustomTagHandler {
   private val pendingLists = Stack<ListTag<*, *>>()
   private val latestPendingList: ListTag<*, *>?
     get() = pendingLists.lastOrNull()
@@ -366,8 +365,4 @@ class LiTagHandler(
     private fun <T : Mark<*>> Spannable.addMark(mark: T) =
       setSpan(mark, length, length, Spanned.SPAN_MARK_MARK)
   }
-
-  override fun getContentDescription(attributes: Attributes): String {
-    return ""
-  }
 }
diff --git a/utility/src/test/java/org/oppia/android/util/parser/html/CustomHtmlContentHandlerTest.kt b/utility/src/test/java/org/oppia/android/util/parser/html/CustomHtmlContentHandlerTest.kt
index 8b11dcba7f0..ab491cf396c 100644
--- a/utility/src/test/java/org/oppia/android/util/parser/html/CustomHtmlContentHandlerTest.kt
+++ b/utility/src/test/java/org/oppia/android/util/parser/html/CustomHtmlContentHandlerTest.kt
@@ -402,6 +402,24 @@ class CustomHtmlContentHandlerTest {
     )
   }
 
+  @Test
+  fun testGetContentDescription_anchorTag_handlesCorrectly() {
+    val contentDescription = CustomHtmlContentHandler.getContentDescription(
+      html =
+        """
+        <p>Visit <a href="https://example.com">Example</a> for more info.</p>
+        <a href="https://another.com">Another Link</a>
+        """.trimIndent(),
+      imageRetriever = mockImageRetriever,
+      customTagHandlers = mapOf()
+    )
+
+    assertThat(contentDescription).isEqualTo(
+      "Visit https://example.com Example for more info.\n" +
+        "https://another.com Another Link"
+    )
+  }
+
   private fun <T : Any> Spannable.getSpansFromWholeString(spanClass: KClass<T>): Array<T> =
     getSpans(/* start= */ 0, /* end= */ length, spanClass.javaObjectType)
 
diff --git a/utility/src/test/java/org/oppia/android/util/parser/html/LiTagHandlerTest.kt b/utility/src/test/java/org/oppia/android/util/parser/html/LiTagHandlerTest.kt
index 13246b7d2d8..3a2f2085326 100644
--- a/utility/src/test/java/org/oppia/android/util/parser/html/LiTagHandlerTest.kt
+++ b/utility/src/test/java/org/oppia/android/util/parser/html/LiTagHandlerTest.kt
@@ -165,57 +165,6 @@ class LiTagHandlerTest {
       .hasLength(4)
   }
 
-  @Test
-  fun testGetContentDescription_handlesNestedOrderedList() {
-    val displayLocale = createDisplayLocaleImpl(US_ENGLISH_CONTEXT)
-    val htmlString = "<p>You should know the following before going on:<br></p>" +
-      "<oppia-ol><oppia-li>The counting numbers (1, 2, 3, 4, 5 ….)</oppia-li>" +
-      "<oppia-li>How to tell whether one counting number is bigger or " +
-      "smaller than another <oppia-ol><oppia-li>Item 1</oppia-li> <oppia-li>Item 2" +
-      "</oppia-li></oppia-ol></oppia-li></oppia-ol>"
-    val liTaghandler = LiTagHandler(context, displayLocale)
-    val contentDescription =
-      CustomHtmlContentHandler.getContentDescription(
-        html = htmlString,
-        imageRetriever = mockImageRetriever,
-        customTagHandlers = mapOf(
-          CUSTOM_LIST_LI_TAG to liTaghandler,
-          CUSTOM_LIST_OL_TAG to liTaghandler
-        )
-      )
-    assertThat(contentDescription).isEqualTo(
-      "You should know the following before going on:\n" +
-        "The counting numbers (1, 2, 3, 4, 5 ….)\n" +
-        "How to tell whether one counting number is bigger or smaller than another \n" +
-        "Item 1 \n" +
-        "Item 2"
-    )
-  }
-
-  @Test
-  fun testGetContentDescription_handlesSimpleUnorderedList() {
-    val displayLocale = createDisplayLocaleImpl(US_ENGLISH_CONTEXT)
-    val htmlString = "<p>You should know the following before going on:<br>" +
-      "<oppia-ul><oppia-li>The counting numbers (1, 2, 3, 4, 5 ….)</oppia-li>" +
-      "<oppia-li>How to tell whether one counting number is bigger or " +
-      "smaller than another</oppia-li></oppia-ul></p>"
-    val liTaghandler = LiTagHandler(context, displayLocale)
-    val contentDescription =
-      CustomHtmlContentHandler.getContentDescription(
-        html = htmlString,
-        imageRetriever = mockImageRetriever,
-        customTagHandlers = mapOf(
-          CUSTOM_LIST_LI_TAG to liTaghandler,
-          CUSTOM_LIST_OL_TAG to liTaghandler
-        )
-      )
-    assertThat(contentDescription).isEqualTo(
-      "You should know the following before going on:\n" +
-        "The counting numbers (1, 2, 3, 4, 5 ….)\n" +
-        "How to tell whether one counting number is bigger or smaller than another"
-    )
-  }
-
   private fun createDisplayLocaleImpl(context: OppiaLocaleContext): DisplayLocaleImpl {
     val formattingLocale = androidLocaleFactory.createOneOffAndroidLocale(context)
     return DisplayLocaleImpl(context, formattingLocale, machineLocale, formatterFactory)