diff --git a/.changelog/5916-fix-roledescription-l10n.md b/.changelog/5916-fix-roledescription-l10n.md
new file mode 100644
index 0000000000..3cae4169cd
--- /dev/null
+++ b/.changelog/5916-fix-roledescription-l10n.md
@@ -0,0 +1,3 @@
+### Fixed
+
+- Fixed the "message" and "attachment" role descriptions being hard-coded in English, in PR [#5916](https://github.com/microsoft/BotFramework-WebChat/pull/5916), by [@OEvgeny](https://github.com/OEvgeny)
diff --git a/__tests__/html2/accessibility/aria-roledescription.localized.html b/__tests__/html2/accessibility/aria-roledescription.localized.html
new file mode 100644
index 0000000000..c610a57080
--- /dev/null
+++ b/__tests__/html2/accessibility/aria-roledescription.localized.html
@@ -0,0 +1,124 @@
+<!doctype html>
+<html lang="en-US">
+  <head>
+    <link href="/assets/index.css" rel="stylesheet" type="text/css" />
+    <!-- Shows the live region, so the snapshots show the copy sent to screen readers. -->
+    <link href="/assets/accessibility.liveRegionAttachment.css" rel="stylesheet" type="text/css" />
+  </head>
+  <body>
+    <main id="webchat"></main>
+    <script type="importmap">
+      {
+        "imports": {
+          "@testduet/wait-for": "https://esm.sh/@testduet/wait-for",
+          "botframework-webchat": "/__dist__/packages/bundle/static/botframework-webchat.js",
+          "botframework-webchat/": "/__dist__/packages/bundle/static/botframework-webchat/",
+          "react": "/__dist__/packages/bundle/static/react.js",
+          "react-dom": "/__dist__/packages/bundle/static/react-dom.js",
+          "react-dom/client": "/__dist__/packages/bundle/static/react-dom/client.js"
+        }
+      }
+    </script>
+    <script type="module">
+      import '/test-harness.mjs';
+      import '/test-page-object.mjs';
+
+      import { waitFor } from '@testduet/wait-for';
+      import { createStoreWithOptions, ReactWebChat } from 'botframework-webchat';
+      import { createElement } from 'react';
+      import { createRoot } from 'react-dom/client';
+
+      // TODO: This is for `createDirectLineEmulator` only, should find ways to eliminate this line.
+      window.WebChat = { createStoreWithOptions };
+
+      run(async function () {
+        const { directLine, store } = testHelpers.createDirectLineEmulator();
+        const root = createRoot(document.getElementById('webchat'));
+        const render = props =>
+          root.render(
+            createElement(ReactWebChat, {
+              directLine,
+              store,
+              // Keeps the live region copy of new messages, so it can be seen in the snapshots.
+              styleOptions: { hideSendBox: true, internalLiveRegionFadeAfter: 60000 },
+              ...props
+            })
+          );
+
+        // Role descriptions of the message and attachments, per activity.
+        // Selects by role, not by the attribute, so an element missing its role description shows up as null.
+        const getRoleDescriptions = () =>
+          pageElements
+            .activities()
+            .map(activity =>
+              Array.from(activity.querySelectorAll('[role="group"], [role="listitem"]'), element =>
+                element.getAttribute('aria-roledescription')
+              )
+            );
+
+        // GIVEN: Web Chat in the default locale (en-US).
+        render({});
+
+        await pageConditions.uiConnected();
+
+        // GIVEN: A message with text and 2 attachments in each attachment layout.
+        for (const attachmentLayout of ['list', 'carousel']) {
+          await directLine.emulateIncomingActivity({
+            attachmentLayout,
+            attachments: [1, 2].map(index => ({
+              content: { title: `Card ${index} (${attachmentLayout})` },
+              contentType: 'application/vnd.microsoft.card.hero'
+            })),
+            from: { role: 'bot' },
+            text: `Message with ${attachmentLayout} attachments`,
+            type: 'message'
+          });
+        }
+
+        await pageConditions.numActivitiesShown(2);
+        await pageConditions.liveRegionStabilized();
+
+        // THEN: A stacked message, then a carousel message, each with its text and 2 cards.
+        // THEN: The live region (top) shows what screen readers announce for each: "Bot said:", the text, and "A card:" per card, without role descriptions.
+        await host.snapshot('local');
+
+        // THEN: Message and attachments are described in English.
+        expect(getRoleDescriptions()).toEqual([
+          ['message', 'attachment', 'attachment'],
+          ['message', 'attachment', 'attachment']
+        ]);
+
+        // WHEN: The host switches to German and provides the strings (no translation in de-DE yet).
+        render({
+          locale: 'de-DE',
+          overrideLocalizedStrings: {
+            ACTIVITY_ATTACHMENT_ARIA_ROLE_ALT: 'Anhang',
+            ACTIVITY_MESSAGE_ARIA_ROLE_ALT: 'Nachricht'
+          }
+        });
+
+        // THEN: Message and attachments are described in German.
+        await waitFor(() =>
+          expect(getRoleDescriptions()).toEqual([
+            ['Nachricht', 'Anhang', 'Anhang'],
+            ['Nachricht', 'Anhang', 'Anhang']
+          ])
+        );
+
+        // WHEN: The bot sends another message.
+        await directLine.emulateIncomingActivity({
+          attachments: [{ content: { title: 'Card 3' }, contentType: 'application/vnd.microsoft.card.hero' }],
+          from: { role: 'bot' },
+          text: 'Message after switching to German',
+          type: 'message'
+        });
+
+        await pageConditions.numActivitiesShown(3);
+        await pageConditions.liveRegionStabilized();
+
+        // THEN: The live region shows the new message announced in German ("Bot sagte:", "Eine Karte:", from de-DE); the earlier copies are re-rendered in German too.
+        await host.snapshot('local');
+      });
+    </script>
+  </body>
+</html>
diff --git a/__tests__/html2/accessibility/aria-roledescription.localized.html.snap-1.png b/__tests__/html2/accessibility/aria-roledescription.localized.html.snap-1.png
new file mode 100644
index 0000000000..752884be7d
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diff --git a/__tests__/html2/accessibility/aria-roledescription.localized.html.snap-2.png b/__tests__/html2/accessibility/aria-roledescription.localized.html.snap-2.png
new file mode 100644
index 0000000000..5c12030c87
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diff --git a/packages/api/src/localization/en-US.json b/packages/api/src/localization/en-US.json
index de235be977..9084114082 100644
--- a/packages/api/src/localization/en-US.json
+++ b/packages/api/src/localization/en-US.json
@@ -12,6 +12,10 @@
   "_ACTIVITY_YOU_SAID_ALT.comment": "This is for screen reader only.",
   "ACTIVITY_BOT_ATTACHED_ALT": "Bot attached:",
   "_ACTIVITY_BOT_ATTACHED_ALT.comment": "This is for screen reader and is narrated before each attachments sent by the bot.",
+  "ACTIVITY_ATTACHMENT_ARIA_ROLE_ALT": "attachment",
+  "_ACTIVITY_ATTACHMENT_ARIA_ROLE_ALT.comment": "This is for screen reader for the aria-roledescription of each attachment in a message, narrated as the type of the element.",
+  "ACTIVITY_MESSAGE_ARIA_ROLE_ALT": "message",
+  "_ACTIVITY_MESSAGE_ARIA_ROLE_ALT.comment": "This is for screen reader for the aria-roledescription of the text of a message, narrated as the type of the element.",
   "ACTIVITY_CODE_ALT": "Code sample: $1",
   "_ACTIVITY_CODE_ALT.comment": "This is for screen reader code sample dialog label, $1 is the dialog title.",
   "ACTIVITY_CONTENT_CAUTION": "AI-generated content may be incorrect",
diff --git a/packages/component/src/Activity/AttachmentRow.tsx b/packages/component/src/Activity/AttachmentRow.tsx
index 5200185893..860bc287f6 100644
--- a/packages/component/src/Activity/AttachmentRow.tsx
+++ b/packages/component/src/Activity/AttachmentRow.tsx
@@ -1,14 +1,17 @@
-import { reactNode, validateProps } from '@msinternal/botframework-webchat-react-valibot';
+import { reactNode, validateProps, type InferReactProps } from '@msinternal/botframework-webchat-react-valibot';
 import { useStyles } from '@msinternal/botframework-webchat-styles/react';
+import { hooks } from 'botframework-webchat-api';
 import cx from 'classnames';
 import React, { memo } from 'react';
-import { boolean, object, optional, pipe, readonly, string, type InferInput } from 'valibot';
+import { boolean, object, optional, pipe, readonly, string } from 'valibot';
 
 import ScreenReaderText from '../ScreenReaderText';
 import Bubble from './Bubble';
 
 import styles from './StackedLayout.module.css';
 
+const { useLocalizer } = hooks;
+
 const attachmentRowPropsSchema = pipe(
   object({
     attachedAlt: string(),
@@ -21,7 +24,7 @@ const attachmentRowPropsSchema = pipe(
   readonly()
 );
 
-type AttachmentRowProps = InferInput<typeof attachmentRowPropsSchema>;
+type AttachmentRowProps = InferReactProps<typeof attachmentRowPropsSchema>;
 
 function AttachmentRow(props: AttachmentRowProps) {
   const {
@@ -33,9 +36,14 @@ function AttachmentRow(props: AttachmentRowProps) {
     showBubble = true
   } = validateProps(attachmentRowPropsSchema, props);
   const classNames = useStyles(styles);
+  const localize = useLocalizer();
 
   return (
-    <div aria-roledescription="attachment" className={classNames['stacked-layout__attachment-row']} role="group">
+    <div
+      aria-roledescription={localize('ACTIVITY_ATTACHMENT_ARIA_ROLE_ALT')}
+      className={classNames['stacked-layout__attachment-row']}
+      role="group"
+    >
       <ScreenReaderText text={attachedAlt} />
       {showBubble ? (
         <Bubble
diff --git a/packages/component/src/Activity/CarouselFilmStrip.js b/packages/component/src/Activity/CarouselFilmStrip.js
index 5812240824..8fe7a71f98 100644
--- a/packages/component/src/Activity/CarouselFilmStrip.js
+++ b/packages/component/src/Activity/CarouselFilmStrip.js
@@ -174,7 +174,11 @@ const CarouselFilmStrip = ({
         </div>
         <div className={classNames['carousel-filmstrip__content']}>
           {!!activityDisplayText && (
-            <div aria-roledescription="message" className={classNames['carousel-filmstrip__message']} role="group">
+            <div
+              aria-roledescription={localize('ACTIVITY_MESSAGE_ARIA_ROLE_ALT')}
+              className={classNames['carousel-filmstrip__message']}
+              role="group"
+            >
               <ScreenReaderText text={greetingAlt} />
               <Bubble
                 className={classNames['carousel-filmstrip__bubble']}
diff --git a/packages/component/src/Activity/CarouselFilmStripAttachment.js b/packages/component/src/Activity/CarouselFilmStripAttachment.js
index fc00369cdf..2754f2bb96 100644
--- a/packages/component/src/Activity/CarouselFilmStripAttachment.js
+++ b/packages/component/src/Activity/CarouselFilmStripAttachment.js
@@ -30,7 +30,7 @@ const CarouselFilmStripAttachment = ({
 
   return (
     <li
-      aria-roledescription="attachment"
+      aria-roledescription={localize('ACTIVITY_ATTACHMENT_ARIA_ROLE_ALT')}
       className={cx(
         classNames['carousel-filmstrip-attachment'],
         {
diff --git a/packages/component/src/Activity/StackedLayout.tsx b/packages/component/src/Activity/StackedLayout.tsx
index 419980ae39..c87e17b270 100644
--- a/packages/component/src/Activity/StackedLayout.tsx
+++ b/packages/component/src/Activity/StackedLayout.tsx
@@ -72,7 +72,11 @@ const StackedLayoutInner = memo(
     return (
       <StackedLayoutMain avatar={showAvatar && renderAvatar && renderAvatar()}>
         {!!(hasDisplayText || messageThing?.abstract[0]) && (
-          <div aria-roledescription="message" className={cx(classNames['stacked-layout__message-row'])} role="group">
+          <div
+            aria-roledescription={localize('ACTIVITY_MESSAGE_ARIA_ROLE_ALT')}
+            className={cx(classNames['stacked-layout__message-row'])}
+            role="group"
+          >
             <ScreenReaderText text={greetingAlt} />
             <Bubble
               className={classNames['stacked-layout__message']}