diff --git a/components/email/__tests__/conversation-reading.test.tsx b/components/email/__tests__/conversation-reading.test.tsx
new file mode 100644
index 000000000..0c8a2592a
--- /dev/null
+++ b/components/email/__tests__/conversation-reading.test.tsx
@@ -0,0 +1,56 @@
+import { describe, expect, it, vi, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+
+// Conversation view: each message frame has its own name and language, and
+// the reading settings reach every message body.
+
+const t = Object.assign(
+  (key: string, params?: Record<string, unknown>) => (params ? `${key} ${JSON.stringify(params)}` : key),
+  { raw: (key: string) => key, rich: (key: string) => key, has: () => true },
+);
+vi.mock('next-intl', () => ({
+  useTranslations: () => t,
+  useLocale: () => 'en',
+}));
+vi.mock('@/hooks/use-wopi-status', () => ({ useWopiStatus: () => ({ enabled: false }), canWopiOpen: () => false }));
+vi.mock('@/hooks/use-own-domain-address', () => ({ useOwnDomainAddress: () => () => false }));
+
+const { ThreadConversationView } = await import('@/components/email/thread-conversation-view');
+const { useSettingsStore } = await import('@/stores/settings-store');
+const { ACCESSIBILITY_DEFAULTS } = await import('@/lib/accessibility-settings');
+
+function mail(id: string, extra: Record<string, unknown> = {}) {
+  return {
+    id, threadId: 't1', mailboxIds: { a: true }, keywords: { $seen: true },
+    from: [{ name: 'Sender', email: 'sender@t.example' }], to: [{ email: 'me@example.org' }],
+    subject: `Subject ${id}`, receivedAt: '2026-09-26T10:00:00Z', size: 1, preview: 'hello', hasAttachment: false,
+    htmlBody: [{ partId: '1', type: 'text/html' }], textBody: [], attachments: [],
+    bodyValues: { '1': { value: '<p>hello <b>there</b></p>' } },
+    ...extra,
+  };
+}
+
+function show(emails: ReturnType<typeof mail>[]) {
+  const latest = emails[emails.length - 1];
+  return render(
+    <ThreadConversationView
+      thread={{ threadId: 't1', emails, latestEmail: latest } as never}
+      emails={emails as never}
+      onBack={() => {}}
+    />,
+  );
+}
+
+beforeEach(() => {
+  useSettingsStore.setState({ ...ACCESSIBILITY_DEFAULTS, fontSize: 'medium' } as never);
+});
+
+describe('conversation message frames', () => {
+  it('are named after their own subject and carry the body language', () => {
+    const { container } = show([mail('a', { htmlBody: [{ partId: '1', type: 'text/html', language: ['it'] }] })]);
+    const iframe = container.querySelector('iframe')!;
+    expect(iframe.getAttribute('title')).toBe('email_viewer.frame_title {"subject":"Subject a"}');
+    expect(iframe.getAttribute('srcdoc')).toMatch(/<html lang="it"/);
+    expect(screen.queryByTitle('Email content')).toBeNull();
+  });
+});
diff --git a/components/email/__tests__/viewer-reading.test.tsx b/components/email/__tests__/viewer-reading.test.tsx
new file mode 100644
index 000000000..78214d969
--- /dev/null
+++ b/components/email/__tests__/viewer-reading.test.tsx
@@ -0,0 +1,96 @@
+import { render, act, screen } from '@testing-library/react';
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import type { Email, Mailbox } from '@/lib/jmap/types';
+import { clearAllHooks } from '@/lib/plugin-hooks';
+
+// How a received message is shown: the body frame's name and language, and
+// the reading settings that reach the body.
+
+const t = Object.assign(
+  (key: string, params?: Record<string, unknown>) => (params ? `${key} ${JSON.stringify(params)}` : key),
+  { raw: (key: string) => key, rich: (key: string) => key, has: () => true },
+);
+vi.mock('next-intl', () => ({
+  useTranslations: () => t,
+  useLocale: () => 'en',
+  useFormatter: () => ({ dateTime: (d: Date | string) => String(d), relativeTime: (d: Date | string) => String(d), number: (n: number) => String(n) }),
+}));
+vi.mock('@/hooks/use-media-query', () => ({
+  useDeviceDetection: () => ({ isMobile: false, isTablet: false, isDesktop: true }),
+  useMediaQuery: () => false,
+  useIsMobile: () => false,
+  useIsDesktop: () => true,
+}));
+vi.mock('@/components/tour/tour-provider', () => ({
+  useTour: () => ({ activeTour: null, startTour: vi.fn(), endTour: vi.fn(), registerStep: vi.fn() }),
+}));
+vi.mock('@/components/plugins/plugin-slot', () => ({ PluginSlot: () => null }));
+vi.mock('@/hooks/use-plugin-slot-offers', () => ({ usePluginSlotOffers: () => [] }));
+
+class NoopResizeObserver {
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+}
+vi.stubGlobal('ResizeObserver', NoopResizeObserver);
+
+const { EmailViewer } = await import('../email-viewer');
+const { useSettingsStore } = await import('@/stores/settings-store');
+const { ACCESSIBILITY_DEFAULTS } = await import('@/lib/accessibility-settings');
+
+const mailboxes = [
+  { id: 'inbox', name: 'Inbox', role: 'inbox', parentId: null, myRights: { mayAddItems: true } },
+] as unknown as Mailbox[];
+
+function message(overrides: Partial<Email> & { html?: string; text?: string } = {}): Email {
+  const { html, text, ...rest } = overrides;
+  const bodyValues: Record<string, { value: string }> = {};
+  if (html !== undefined) bodyValues.h = { value: html };
+  if (text !== undefined) bodyValues.t = { value: text };
+  return {
+    id: 'm1', blobId: 'b1', threadId: 't1', mailboxIds: { inbox: true }, keywords: { $seen: true },
+    from: [{ name: 'Alice', email: 'alice@example.com' }], to: [{ name: 'Bob', email: 'bob@example.com' }],
+    subject: 'Bonjour', receivedAt: '2026-01-01T00:00:00Z', preview: 'Hello', hasAttachment: false, size: 100,
+    htmlBody: html !== undefined ? [{ partId: 'h', type: 'text/html' }] : [],
+    textBody: text !== undefined ? [{ partId: 't', type: 'text/plain' }] : html !== undefined ? [{ partId: 'h', type: 'text/html' }] : [],
+    attachments: [],
+    bodyValues,
+    ...rest,
+  } as unknown as Email;
+}
+
+async function show(email: Email) {
+  const view = render(
+    <EmailViewer email={email} isLoading={false} mailboxes={mailboxes} selectedMailbox="inbox" currentMailboxRole="inbox" />,
+  );
+  await act(async () => { await new Promise((r) => setTimeout(r, 20)); });
+  return view;
+}
+
+beforeEach(() => {
+  clearAllHooks();
+  useSettingsStore.setState({ ...ACCESSIBILITY_DEFAULTS, fontSize: 'medium' } as never);
+});
+
+describe('message body frame', () => {
+  it('is named after the subject and carries the mail language', async () => {
+    const { container } = await show(message({
+      html: '<html lang="fr"><body><p>Bonjour tout le monde</p></body></html>',
+    }));
+    const iframe = container.querySelector('iframe')!;
+    expect(iframe.getAttribute('title')).toBe('frame_title {"subject":"Bonjour"}');
+    expect(iframe.getAttribute('srcdoc')).toMatch(/^<!DOCTYPE html>\s*<html lang="fr"/);
+  });
+
+  it('is named after the sender when there is no subject, with no language guessed', async () => {
+    const { container } = await show(message({ subject: '', html: '<p>Hi there, <b>friend</b></p>' }));
+    const iframe = container.querySelector('iframe')!;
+    expect(iframe.getAttribute('title')).toBe('frame_title_from {"sender":"Alice"}');
+    expect(iframe.getAttribute('srcdoc')).not.toMatch(/<html[^>]*\slang=/);
+  });
+
+  it('marks a plain-text body with its Content-Language', async () => {
+    await show(message({ text: 'Hallo zusammen', textBody: [{ partId: 't', type: 'text/plain', language: ['de'] }] as never }));
+    expect(screen.getByText('Hallo zusammen').closest('[lang]')?.getAttribute('lang')).toBe('de');
+  });
+});
diff --git a/components/email/email-viewer.tsx b/components/email/email-viewer.tsx
index 45302a079..7da947bbe 100644
--- a/components/email/email-viewer.tsx
+++ b/components/email/email-viewer.tsx
@@ -6,6 +6,7 @@ import { attachmentDownloadFilename, attachmentsBundleFilename, DEFAULT_ATTACHME
 import { EML_IMPORT_ACCEPT, expandImportableEmails } from "@/lib/eml-import";
 import { TRANSPARENT_BLOCKED_PIXEL, applyNewTabToAnchor, emailIframeCsp, escapeHtml, isExternalResourceUrl, isOpenableLinkHref, plainTextToSafeHtml, sanitizeEmailBodyForIframe, sanitizeEmailHtml, sanitizePlainTextRenderedHtml } from "@/lib/email-sanitization";
 import { getRenderableHtmlBody } from "@/lib/email-body-selection";
+import { mailLanguage } from "@/lib/mail-language";
 import { collectReferencedCids, isEmbeddedInBody, normalizeCid, rewriteCidReferences } from "@/lib/attachment-visibility";
 import { collapsePlainTextQuotes, setupQuoteCollapse } from "@/lib/quote-collapse";
 import { DARK_PENDING_CLASS, applyEmailDarkMode, emailColorScheme, emailDarkModeCss, emailHasNativeDarkMode as htmlHasNativeDarkMode, resolveColorSchemeMedia } from "@/lib/email-dark-mode";
@@ -3153,6 +3154,14 @@ export function EmailViewer({
     ? emailViewDarkOverride
     : (emailAlwaysLightMode ? false : resolvedTheme === 'dark');
 
+  // The body's language (Content-Language or the HTML's own lang), so a
+  // screen reader switches voice for it; none when the mail doesn't say.
+  const bodyLanguage = useMemo(() => mailLanguage(email, email ? getRenderableHtmlBody(email) : null), [email]);
+  const frameSender = email?.from?.[0];
+  const frameTitle = email?.subject
+    ? t('frame_title', { subject: email.subject })
+    : t('frame_title_from', { sender: frameSender?.name || frameSender?.email || t('unknown_sender') });
+
   const emailIframeSrcDoc = useMemo(() => {
     if (!effectiveEmailContent.isHtml) return '';
 
@@ -3195,7 +3204,7 @@ export function EmailViewer({
     const iframeCsp = emailIframeCsp(effectiveEmailContent.externalBlocked);
 
     return `<!DOCTYPE html>
-<html class="${isDark ? DARK_PENDING_CLASS : ''}" style="color-scheme: ${colorScheme};"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1">
+<html${bodyLanguage ? ` lang="${bodyLanguage}"` : ''} class="${isDark ? DARK_PENDING_CLASS : ''}" style="color-scheme: ${colorScheme};"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1">
 <meta http-equiv="Content-Security-Policy" content="${iframeCsp}">
 <meta name="referrer" content="no-referrer">
 <meta http-equiv="x-dns-prefetch-control" content="off">
@@ -3247,7 +3256,7 @@ export function EmailViewer({
   ${wordHtmlCSS}
   ${darkModeCSS}
 </style></head><body dir="auto">${resolveColorSchemeMedia(effectiveEmailContent.html, isDark)}<style>html,body{height:auto!important;min-height:0!important;max-height:none!important}</style></body></html>`;
-  }, [effectiveEmailContent.html, effectiveEmailContent.isHtml, effectiveEmailContent.hasStyleTag, effectiveEmailContent.externalBlocked, isDark, emailHasNativeDarkMode, messageSpacing]);
+  }, [effectiveEmailContent.html, effectiveEmailContent.isHtml, effectiveEmailContent.hasStyleTag, effectiveEmailContent.externalBlocked, isDark, emailHasNativeDarkMode, messageSpacing, bodyLanguage]);
 
   // Unblocking external content is handled by rebuilding the iframe srcDoc:
   // toggling allowExternalContent (both "Load images" and "Trust sender" set
@@ -6156,7 +6165,7 @@ export function EmailViewer({
                 ref={iframeRef}
                 srcDoc={emailIframeSrcDoc}
                 sandbox="allow-same-origin allow-popups allow-popups-to-escape-sandbox"
-                title="Email content"
+                title={frameTitle}
                 className="w-full border-0 block"
                 scrolling="no"
                 style={{ minHeight: '100px', colorScheme: emailColorScheme(isDark, emailHasNativeDarkMode) }}
@@ -6167,6 +6176,7 @@ export function EmailViewer({
                 ref={setPlainBodyEl}
                 className="email-content-text text-foreground"
                 dir="auto"
+                lang={bodyLanguage ?? undefined}
                 data-plugin-source="email-body"
                 data-email-id={email?.id}
                 onContextMenu={(e) => selectionMenu.onElementContextMenu(e, email?.id)}
diff --git a/components/email/thread-conversation-view.tsx b/components/email/thread-conversation-view.tsx
index e694ef692..d668633e4 100644
--- a/components/email/thread-conversation-view.tsx
+++ b/components/email/thread-conversation-view.tsx
@@ -15,6 +15,7 @@ import { ExternalSenderChip } from "./external-sender-chip";
 import { collectReferencedCids, isEmbeddedInBody, normalizeCid, rewriteCidReferences } from "@/lib/attachment-visibility";
 import { collapsePlainTextQuotes, setupQuoteCollapse } from "@/lib/quote-collapse";
 import { fitEmailBodyWidth } from "@/lib/email-fit-width";
+import { mailLanguage } from "@/lib/mail-language";
 import { DARK_PENDING_CLASS, applyEmailDarkMode, emailDarkModeCss } from "@/lib/email-dark-mode";
 import { useThemeStore } from "@/stores/theme-store";
 import { useShallow } from "zustand/react/shallow";
@@ -756,13 +757,20 @@ export function ConversationEmailBody({
   // the host page. CSP <meta> is defense-in-depth in case the sanitizer ever
   // emits a <script> tag through a parser quirk.
   const iframeRef = useRef<HTMLIFrameElement>(null);
+  // The body's language for screen readers (see mailLanguage), and a frame
+  // title that tells this message from the others in the conversation.
+  const bodyLanguage = useMemo(() => mailLanguage(email, getRenderableHtmlBody(email)), [email]);
+  const frameSender = email.from?.[0];
+  const frameTitle = email.subject
+    ? t('email_viewer.frame_title', { subject: email.subject })
+    : t('email_viewer.frame_title_from', { sender: frameSender?.name || frameSender?.email || t('email_viewer.unknown_sender') });
   const emailIframeSrcDoc = useMemo(() => {
     if (!emailContent.isHtml || !emailContent.html) return '';
     // Strict while external content is blocked: the network-level backstop
     // for whatever the DOM walk above cannot see.
     const csp = emailIframeCsp(!allowExternal);
     // Colours are rewritten after load (applyEmailDarkMode in handleIframeLoad).
-    return `<!DOCTYPE html><html class="${isDark ? DARK_PENDING_CLASS : ''}"><head>
+    return `<!DOCTYPE html><html${bodyLanguage ? ` lang="${bodyLanguage}"` : ''} class="${isDark ? DARK_PENDING_CLASS : ''}"><head>
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
 <meta http-equiv="Content-Security-Policy" content="${csp}">
@@ -794,7 +802,7 @@ export function ConversationEmailBody({
   pre { white-space: pre-wrap; word-wrap: break-word; }
   ${isDark ? emailDarkModeCss() : ''}
 </style></head><body dir="auto">${emailContent.html}</body></html>`;
-  }, [emailContent.isHtml, emailContent.html, allowExternal, isDark]);
+  }, [emailContent.isHtml, emailContent.html, allowExternal, isDark, bodyLanguage]);
   useLayoutEffect(() => { setHtmlBodyEl(null); }, [emailIframeSrcDoc]);
   // One object per body: React writes innerHTML again whenever this object
   // changes, dropping whatever was mounted in the body.
@@ -911,7 +919,7 @@ export function ConversationEmailBody({
             ref={iframeRef}
             srcDoc={emailIframeSrcDoc}
             sandbox="allow-same-origin allow-popups allow-popups-to-escape-sandbox"
-            title="Email content"
+            title={frameTitle}
             className="w-full border-0 block"
             scrolling="no"
             style={{ minHeight: '60px' }}
@@ -923,6 +931,7 @@ export function ConversationEmailBody({
             // Its own direction, as in the reader: English text in an Arabic
             // UI read "1+" and ".change".
             dir="auto"
+            lang={bodyLanguage ?? undefined}
             className={cn(
               "prose prose-sm max-w-none",
               !emailAlwaysLightMode && "dark:prose-invert",
diff --git a/lib/__tests__/mail-language.test.ts b/lib/__tests__/mail-language.test.ts
new file mode 100644
index 000000000..7cdc69d80
--- /dev/null
+++ b/lib/__tests__/mail-language.test.ts
@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest';
+import { htmlDeclaredLanguage, mailLanguage } from '@/lib/mail-language';
+
+describe('mailLanguage', () => {
+  it('prefers the body part Content-Language', () => {
+    expect(mailLanguage({ htmlBody: [{ language: ['fr-CA'] } as never], textBody: [], headers: { 'Content-Language': 'de' } }, '<html lang="en">')).toBe('fr-CA');
+  });
+
+  it('falls back to the message header, first tag of a list', () => {
+    expect(mailLanguage({ htmlBody: [], textBody: [], headers: { 'content-language': 'nl, en' } }, null)).toBe('nl');
+  });
+
+  it('falls back to the lang the HTML declares', () => {
+    expect(mailLanguage({ htmlBody: [], textBody: [] }, '<html xmlns="x" lang="es"><body>hola')).toBe('es');
+    // Word sets it on <body>.
+    expect(htmlDeclaredLanguage('<html><body lang=DE link=blue>')).toBe('DE');
+  });
+
+  it('is null when the mail says nothing or something that is not a tag', () => {
+    expect(mailLanguage({ htmlBody: [], textBody: [] }, '<p>hi</p>')).toBeNull();
+    expect(mailLanguage({ htmlBody: [], textBody: [], headers: { 'Content-Language': '"><script>' } }, null)).toBeNull();
+  });
+});
diff --git a/lib/mail-language.ts b/lib/mail-language.ts
new file mode 100644
index 000000000..5b8f97820
--- /dev/null
+++ b/lib/mail-language.ts
@@ -0,0 +1,48 @@
+import type { Email } from '@/lib/jmap/types';
+
+/** A BCP 47 tag as mail carries it: "fr", "de-CH", "zh-Hant-TW". */
+const LANGUAGE_TAG = /^[a-z]{2,3}(?:-[a-z0-9]{1,8})*$/i;
+
+function cleanTag(value: string | null | undefined): string | null {
+  if (!value) return null;
+  // Content-Language may list several ("de, en"); the first one is the body's.
+  const first = value.split(',')[0].trim();
+  return LANGUAGE_TAG.test(first) ? first : null;
+}
+
+function headerValue(headers: Email['headers'], name: string): string | null {
+  if (!headers || Array.isArray(headers)) return null;
+  const key = Object.keys(headers).find((k) => k.toLowerCase() === name);
+  if (!key) return null;
+  const value = headers[key];
+  return Array.isArray(value) ? value[0] ?? null : value ?? null;
+}
+
+/** The `lang` an HTML body declares on its <html> or <body> element. */
+export function htmlDeclaredLanguage(html: string | null | undefined): string | null {
+  if (!html) return null;
+  const head = html.slice(0, 20000);
+  for (const tag of ['html', 'body']) {
+    const match = new RegExp(`<${tag}\\b[^>]*?\\s(?:xml:)?lang\\s*=\\s*["']?([^"'\\s>]+)`, 'i').exec(head);
+    const lang = cleanTag(match?.[1]);
+    if (lang) return lang;
+  }
+  return null;
+}
+
+/**
+ * The language a message body is written in, for `lang` on the frame it
+ * renders in, so a screen reader reads a French mail with a French voice.
+ * Taken from the body part's Content-Language, the message header, or the
+ * HTML's own `lang`, in that order; null when the mail doesn't say.
+ */
+export function mailLanguage(
+  email: Pick<Email, 'htmlBody' | 'textBody' | 'headers'> | null | undefined,
+  html?: string | null,
+): string | null {
+  if (!email) return htmlDeclaredLanguage(html);
+  const part = email.htmlBody?.[0] ?? email.textBody?.[0];
+  return cleanTag(part?.language?.[0])
+    ?? cleanTag(headerValue(email.headers, 'content-language'))
+    ?? htmlDeclaredLanguage(html);
+}
diff --git a/locales/ar/common.json b/locales/ar/common.json
index 05faf9e78..6b8ba17d1 100644
--- a/locales/ar/common.json
+++ b/locales/ar/common.json
@@ -767,7 +767,9 @@
       "saved_to": "في {folder}",
       "failed": "تعذّر الحفظ في الملفات",
       "load_failed": "تعذّر تحميل مجلداتك. حاول مرة أخرى."
-    }
+    },
+    "frame_title": "الرسالة: {subject}",
+    "frame_title_from": "رسالة من {sender}"
   },
   "external_mail": {
     "sender_label": "خارجي",
diff --git a/locales/ca/common.json b/locales/ca/common.json
index cfafba742..7ead50a37 100644
--- a/locales/ca/common.json
+++ b/locales/ca/common.json
@@ -767,7 +767,9 @@
       "saved_to": "A {folder}",
       "failed": "No s'ha pogut desar a Fitxers",
       "load_failed": "No s'han pogut carregar les carpetes. Torna-ho a provar."
-    }
+    },
+    "frame_title": "Missatge: {subject}",
+    "frame_title_from": "Missatge de {sender}"
   },
   "external_mail": {
     "sender_label": "Extern",
diff --git a/locales/cs/common.json b/locales/cs/common.json
index 754b2a1c9..4e3c328c9 100644
--- a/locales/cs/common.json
+++ b/locales/cs/common.json
@@ -767,7 +767,9 @@
       "saved_to": "Do složky {folder}",
       "failed": "Nepodařilo se uložit do Souborů",
       "load_failed": "Složky se nepodařilo načíst. Zkuste to znovu."
-    }
+    },
+    "frame_title": "Zpráva: {subject}",
+    "frame_title_from": "Zpráva od {sender}"
   },
   "external_mail": {
     "sender_label": "Externí",
diff --git a/locales/da/common.json b/locales/da/common.json
index 594f8de76..a11350791 100644
--- a/locales/da/common.json
+++ b/locales/da/common.json
@@ -767,7 +767,9 @@
       "saved_to": "I {folder}",
       "failed": "Kunne ikke gemme i Filer",
       "load_failed": "Mapperne kunne ikke indlæses. Prøv igen."
-    }
+    },
+    "frame_title": "Besked: {subject}",
+    "frame_title_from": "Besked fra {sender}"
   },
   "external_mail": {
     "sender_label": "Ekstern",
diff --git a/locales/de/common.json b/locales/de/common.json
index c8867f96f..c037c244b 100644
--- a/locales/de/common.json
+++ b/locales/de/common.json
@@ -767,7 +767,9 @@
       "saved_to": "In {folder}",
       "failed": "Konnte nicht in Dateien gespeichert werden",
       "load_failed": "Ihre Ordner konnten nicht geladen werden. Versuchen Sie es erneut."
-    }
+    },
+    "frame_title": "Nachricht: {subject}",
+    "frame_title_from": "Nachricht von {sender}"
   },
   "external_mail": {
     "sender_label": "Extern",
diff --git a/locales/en/common.json b/locales/en/common.json
index 801086856..91656d125 100644
--- a/locales/en/common.json
+++ b/locales/en/common.json
@@ -767,7 +767,9 @@
       "load_failed": "Couldn't load your folders. Try again."
     },
     "plugin_panel_show": "Show plugin panel",
-    "plugin_panel_hide": "Hide plugin panel"
+    "plugin_panel_hide": "Hide plugin panel",
+    "frame_title": "Message: {subject}",
+    "frame_title_from": "Message from {sender}"
   },
   "external_mail": {
     "sender_label": "External",
diff --git a/locales/es/common.json b/locales/es/common.json
index 99e76b89c..916fb5a5a 100644
--- a/locales/es/common.json
+++ b/locales/es/common.json
@@ -767,7 +767,9 @@
       "saved_to": "En {folder}",
       "failed": "No se pudo guardar en Archivos",
       "load_failed": "No se pudieron cargar tus carpetas. Vuelve a intentarlo."
-    }
+    },
+    "frame_title": "Mensaje: {subject}",
+    "frame_title_from": "Mensaje de {sender}"
   },
   "external_mail": {
     "sender_label": "Externo",
diff --git a/locales/et/common.json b/locales/et/common.json
index 6a81f9706..472073a52 100644
--- a/locales/et/common.json
+++ b/locales/et/common.json
@@ -767,7 +767,9 @@
       "saved_to": "Kausta {folder}",
       "failed": "Failidesse salvestamine ei õnnestunud",
       "load_failed": "Kaustu ei õnnestunud laadida. Proovige uuesti."
-    }
+    },
+    "frame_title": "Kiri: {subject}",
+    "frame_title_from": "Kiri saatjalt {sender}"
   },
   "external_mail": {
     "sender_label": "Väline",
diff --git a/locales/fa/common.json b/locales/fa/common.json
index 8d5ac8054..665ccd173 100644
--- a/locales/fa/common.json
+++ b/locales/fa/common.json
@@ -767,7 +767,9 @@
       "saved_to": "در {folder}",
       "failed": "ذخیره در فایل‌ها ممکن نشد",
       "load_failed": "پوشه‌ها بارگذاری نشدند. دوباره امتحان کنید."
-    }
+    },
+    "frame_title": "پیام: {subject}",
+    "frame_title_from": "پیام از {sender}"
   },
   "external_mail": {
     "sender_label": "خارجی",
diff --git a/locales/fr/common.json b/locales/fr/common.json
index 6530672fa..88c62c9f2 100644
--- a/locales/fr/common.json
+++ b/locales/fr/common.json
@@ -767,7 +767,9 @@
       "saved_to": "Dans {folder}",
       "failed": "Impossible d'enregistrer dans Fichiers",
       "load_failed": "Impossible de charger vos dossiers. Réessayez."
-    }
+    },
+    "frame_title": "Message : {subject}",
+    "frame_title_from": "Message de {sender}"
   },
   "external_mail": {
     "sender_label": "Externe",
diff --git a/locales/he/common.json b/locales/he/common.json
index 0efb0a83b..6f9b84821 100644
--- a/locales/he/common.json
+++ b/locales/he/common.json
@@ -732,7 +732,9 @@
       "saved_to": "ב{folder}",
       "failed": "לא ניתן היה לשמור בקבצים",
       "load_failed": "לא ניתן היה לטעון את התיקיות. נסו שוב."
-    }
+    },
+    "frame_title": "הודעה: {subject}",
+    "frame_title_from": "הודעה מאת {sender}"
   },
   "external_mail": {
     "sender_label": "חיצוני",
diff --git a/locales/hu/common.json b/locales/hu/common.json
index faa0b6a54..1bc4047f7 100644
--- a/locales/hu/common.json
+++ b/locales/hu/common.json
@@ -767,7 +767,9 @@
       "saved_to": "Ide: {folder}",
       "failed": "Nem sikerült menteni a Fájlokba",
       "load_failed": "Nem sikerült betölteni a mappákat. Próbálja újra."
-    }
+    },
+    "frame_title": "Üzenet: {subject}",
+    "frame_title_from": "Üzenet tőle: {sender}"
   },
   "external_mail": {
     "sender_label": "Külső",
diff --git a/locales/it/common.json b/locales/it/common.json
index 3b31f50c5..1df084d99 100644
--- a/locales/it/common.json
+++ b/locales/it/common.json
@@ -767,7 +767,9 @@
       "saved_to": "In {folder}",
       "failed": "Impossibile salvare in File",
       "load_failed": "Impossibile caricare le cartelle. Riprova."
-    }
+    },
+    "frame_title": "Messaggio: {subject}",
+    "frame_title_from": "Messaggio da {sender}"
   },
   "external_mail": {
     "sender_label": "Esterno",
diff --git a/locales/ja/common.json b/locales/ja/common.json
index 2039dd381..4ca386f7c 100644
--- a/locales/ja/common.json
+++ b/locales/ja/common.json
@@ -767,7 +767,9 @@
       "saved_to": "{folder} に保存",
       "failed": "ファイルに保存できませんでした",
       "load_failed": "フォルダを読み込めませんでした。もう一度お試しください。"
-    }
+    },
+    "frame_title": "メッセージ: {subject}",
+    "frame_title_from": "{sender} からのメッセージ"
   },
   "external_mail": {
     "sender_label": "外部",
diff --git a/locales/ko/common.json b/locales/ko/common.json
index 7c3e72540..df0b6032d 100644
--- a/locales/ko/common.json
+++ b/locales/ko/common.json
@@ -767,7 +767,9 @@
       "saved_to": "{folder}에 저장",
       "failed": "파일에 저장하지 못했어요",
       "load_failed": "폴더를 불러오지 못했어요. 다시 시도하세요."
-    }
+    },
+    "frame_title": "메시지: {subject}",
+    "frame_title_from": "{sender}님의 메시지"
   },
   "external_mail": {
     "sender_label": "외부",
diff --git a/locales/lv/common.json b/locales/lv/common.json
index 148ff5c5e..16524c014 100644
--- a/locales/lv/common.json
+++ b/locales/lv/common.json
@@ -767,7 +767,9 @@
       "saved_to": "Mapē {folder}",
       "failed": "Neizdevās saglabāt failos",
       "load_failed": "Neizdevās ielādēt mapes. Mēģiniet vēlreiz."
-    }
+    },
+    "frame_title": "Ziņojums: {subject}",
+    "frame_title_from": "Ziņojums no {sender}"
   },
   "external_mail": {
     "sender_label": "Ārējs",
diff --git a/locales/mn/common.json b/locales/mn/common.json
index 0d4abb5c3..2a72ee35f 100644
--- a/locales/mn/common.json
+++ b/locales/mn/common.json
@@ -767,7 +767,9 @@
       "saved_to": "{folder}-д",
       "failed": "Файлд хадгалж чадсангүй",
       "load_failed": "Хавтсуудыг ачаалж чадсангүй. Дахин оролдоно уу."
-    }
+    },
+    "frame_title": "Захидал: {subject}",
+    "frame_title_from": "{sender}-с ирсэн захидал"
   },
   "external_mail": {
     "sender_label": "Гадаад",
diff --git a/locales/nb/common.json b/locales/nb/common.json
index 76c98d6cc..8e1ceed56 100644
--- a/locales/nb/common.json
+++ b/locales/nb/common.json
@@ -767,7 +767,9 @@
       "saved_to": "I {folder}",
       "failed": "Kunne ikke lagre i Filer",
       "load_failed": "Kunne ikke laste inn mappene. Prøv igjen."
-    }
+    },
+    "frame_title": "Melding: {subject}",
+    "frame_title_from": "Melding fra {sender}"
   },
   "external_mail": {
     "sender_label": "Ekstern",
diff --git a/locales/nl/common.json b/locales/nl/common.json
index 0b052a082..4481971af 100644
--- a/locales/nl/common.json
+++ b/locales/nl/common.json
@@ -767,7 +767,9 @@
       "saved_to": "In {folder}",
       "failed": "Kon niet opslaan in Bestanden",
       "load_failed": "Kon je mappen niet laden. Probeer het opnieuw."
-    }
+    },
+    "frame_title": "Bericht: {subject}",
+    "frame_title_from": "Bericht van {sender}"
   },
   "external_mail": {
     "sender_label": "Extern",
diff --git a/locales/pl/common.json b/locales/pl/common.json
index b199fa0e1..681cef7dd 100644
--- a/locales/pl/common.json
+++ b/locales/pl/common.json
@@ -767,7 +767,9 @@
       "saved_to": "W folderze {folder}",
       "failed": "Nie udało się zapisać w Plikach",
       "load_failed": "Nie udało się wczytać folderów. Spróbuj ponownie."
-    }
+    },
+    "frame_title": "Wiadomość: {subject}",
+    "frame_title_from": "Wiadomość od {sender}"
   },
   "external_mail": {
     "sender_label": "Zewnętrzny",
diff --git a/locales/pt/common.json b/locales/pt/common.json
index 53910bc40..65ebdea72 100644
--- a/locales/pt/common.json
+++ b/locales/pt/common.json
@@ -767,7 +767,9 @@
       "saved_to": "Em {folder}",
       "failed": "Não foi possível guardar em Ficheiros",
       "load_failed": "Não foi possível carregar as pastas. Tente novamente."
-    }
+    },
+    "frame_title": "Mensagem: {subject}",
+    "frame_title_from": "Mensagem de {sender}"
   },
   "external_mail": {
     "sender_label": "Externo",
diff --git a/locales/ro/common.json b/locales/ro/common.json
index cb1624d63..1b2e806c2 100644
--- a/locales/ro/common.json
+++ b/locales/ro/common.json
@@ -767,7 +767,9 @@
       "saved_to": "În {folder}",
       "failed": "Nu s-a putut salva în Fișiere",
       "load_failed": "Dosarele nu au putut fi încărcate. Încearcă din nou."
-    }
+    },
+    "frame_title": "Mesaj: {subject}",
+    "frame_title_from": "Mesaj de la {sender}"
   },
   "external_mail": {
     "sender_label": "Extern",
diff --git a/locales/ru/common.json b/locales/ru/common.json
index 9f1b0567a..b702cd4e3 100644
--- a/locales/ru/common.json
+++ b/locales/ru/common.json
@@ -767,7 +767,9 @@
       "saved_to": "В папку {folder}",
       "failed": "Не удалось сохранить в «Файлы»",
       "load_failed": "Не удалось загрузить папки. Повторите попытку."
-    }
+    },
+    "frame_title": "Письмо: {subject}",
+    "frame_title_from": "Письмо от {sender}"
   },
   "external_mail": {
     "sender_label": "Внешнее",
diff --git a/locales/sk/common.json b/locales/sk/common.json
index e3db3a2e2..0a5965bf9 100644
--- a/locales/sk/common.json
+++ b/locales/sk/common.json
@@ -767,7 +767,9 @@
       "saved_to": "Do priečinka {folder}",
       "failed": "Nepodarilo sa uložiť do Súborov",
       "load_failed": "Priečinky sa nepodarilo načítať. Skúste to znova."
-    }
+    },
+    "frame_title": "Správa: {subject}",
+    "frame_title_from": "Správa od {sender}"
   },
   "external_mail": {
     "sender_label": "Externé",
diff --git a/locales/th/common.json b/locales/th/common.json
index bff5f4cc9..f5a79da2d 100644
--- a/locales/th/common.json
+++ b/locales/th/common.json
@@ -1697,7 +1697,9 @@
       "load_failed": "ไม่สามารถโหลดโฟลเดอร์ได้ ลองอีกครั้ง"
     },
     "plugin_panel_show": "แสดงแถบปลั๊กอิน",
-    "plugin_panel_hide": "ซ่อนแถบปลั๊กอิน"
+    "plugin_panel_hide": "ซ่อนแถบปลั๊กอิน",
+    "frame_title": "ข้อความ: {subject}",
+    "frame_title_from": "ข้อความจาก {sender}"
   },
   "external_mail": {
     "sender_label": "ภายนอก",
diff --git a/locales/tr/common.json b/locales/tr/common.json
index 86f6753cf..b43b217cd 100644
--- a/locales/tr/common.json
+++ b/locales/tr/common.json
@@ -767,7 +767,9 @@
       "saved_to": "{folder} içine",
       "failed": "Dosyalar'a kaydedilemedi",
       "load_failed": "Klasörler yüklenemedi. Yeniden deneyin."
-    }
+    },
+    "frame_title": "İleti: {subject}",
+    "frame_title_from": "{sender} adlı kişiden ileti"
   },
   "external_mail": {
     "sender_label": "Harici",
diff --git a/locales/uk/common.json b/locales/uk/common.json
index cb4848a43..c5b2eca29 100644
--- a/locales/uk/common.json
+++ b/locales/uk/common.json
@@ -767,7 +767,9 @@
       "saved_to": "У теку {folder}",
       "failed": "Не вдалося зберегти у «Файли»",
       "load_failed": "Не вдалося завантажити теки. Спробуйте ще раз."
-    }
+    },
+    "frame_title": "Лист: {subject}",
+    "frame_title_from": "Лист від {sender}"
   },
   "external_mail": {
     "sender_label": "Зовнішнє",
diff --git a/locales/zh-TW/common.json b/locales/zh-TW/common.json
index beccad41b..3466a2c5a 100644
--- a/locales/zh-TW/common.json
+++ b/locales/zh-TW/common.json
@@ -767,7 +767,9 @@
       "saved_to": "在 {folder} 中",
       "failed": "無法儲存到檔案",
       "load_failed": "無法載入資料夾。請再試一次。"
-    }
+    },
+    "frame_title": "郵件：{subject}",
+    "frame_title_from": "來自 {sender} 的郵件"
   },
   "external_mail": {
     "sender_label": "外部",
diff --git a/locales/zh/common.json b/locales/zh/common.json
index 54174aa3c..a137d0d7c 100644
--- a/locales/zh/common.json
+++ b/locales/zh/common.json
@@ -767,7 +767,9 @@
       "saved_to": "在 {folder} 中",
       "failed": "无法保存到文件",
       "load_failed": "无法加载文件夹。请重试。"
-    }
+    },
+    "frame_title": "邮件：{subject}",
+    "frame_title_from": "来自 {sender} 的邮件"
   },
   "external_mail": {
     "sender_label": "外部",