diff --git a/App.tsx b/App.tsx
index 81c98102..e00140b3 100644
--- a/App.tsx
+++ b/App.tsx
@@ -200,6 +200,16 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
   const hasContacts = useHasContacts();
   const hasFiles = useHasFiles();
   const disabledTabStyle = { opacity: 0.4 } as const;
+  const t = useLocaleStore((state) => state.t);
+  // The webmail's navigation names; a tab the server lacks says so.
+  const tabLabels = {
+    mail: t('sidebar.mail', 'Mail'),
+    calendar: t('sidebar.calendar', 'Calendar'),
+    contacts: t('sidebar.contacts', 'Contacts'),
+    files: t('sidebar.files', 'Files'),
+    settings: t('sidebar.settings', 'Settings'),
+  };
+  const unavailable = (name: string) => t('sidebar.tab_unavailable', '{name} (unavailable)', { name });
 
   return (
     <View style={{ flex: 1, backgroundColor: c.background }}>
@@ -231,6 +241,7 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
       <Tab.Screen
         name="Mail"
         options={{
+          title: tabLabels.mail,
           tabBarIcon: ({ color, size }) => <Mail size={size} color={color} />,
           tabBarBadge: inboxUnreadCount > 0 ? (inboxUnreadCount > 99 ? '99+' : inboxUnreadCount) : undefined,
           tabBarBadgeStyle: {
@@ -276,9 +287,10 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
         name="Calendar"
         component={CalendarScreen}
         options={{
+          title: tabLabels.calendar,
           tabBarIcon: ({ color, size }) => <Calendar size={size} color={color} />,
           tabBarItemStyle: hasCalendar ? undefined : disabledTabStyle,
-          tabBarAccessibilityLabel: hasCalendar ? 'Calendar' : 'Calendar (unavailable)',
+          tabBarAccessibilityLabel: hasCalendar ? tabLabels.calendar : unavailable(tabLabels.calendar),
         }}
         listeners={{
           tabPress: (e) => {
@@ -290,9 +302,10 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
         name="Contacts"
         component={ContactsScreen}
         options={{
+          title: tabLabels.contacts,
           tabBarIcon: ({ color, size }) => <BookUser size={size} color={color} />,
           tabBarItemStyle: hasContacts ? undefined : disabledTabStyle,
-          tabBarAccessibilityLabel: hasContacts ? 'Contacts' : 'Contacts (unavailable)',
+          tabBarAccessibilityLabel: hasContacts ? tabLabels.contacts : unavailable(tabLabels.contacts),
         }}
         listeners={{
           tabPress: (e) => {
@@ -304,9 +317,10 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
         name="Files"
         component={FilesScreen}
         options={{
+          title: tabLabels.files,
           tabBarIcon: ({ color, size }) => <HardDrive size={size} color={color} />,
           tabBarItemStyle: hasFiles ? undefined : disabledTabStyle,
-          tabBarAccessibilityLabel: hasFiles ? 'Files' : 'Files (unavailable)',
+          tabBarAccessibilityLabel: hasFiles ? tabLabels.files : unavailable(tabLabels.files),
         }}
         listeners={{
           tabPress: (e) => {
@@ -317,6 +331,7 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
       <Tab.Screen
         name="Settings"
         options={{
+          title: tabLabels.settings,
           tabBarIcon: ({ color, size }) => <Settings size={size} color={color} />,
         }}
       >
@@ -332,6 +347,7 @@ export default function App() {
   const isAuthenticated = useAuthStore((state) => state.isAuthenticated);
   const client = useAuthStore((state) => state.client);
   const restoreSession = useAuthStore((state) => state.restoreSession);
+  const t = useLocaleStore((state) => state.t);
 
   // Resolve the user's theme preference to a concrete light/dark style for the
   // system status bar. The rest of the app's colors are still hard-coded dark
@@ -700,7 +716,7 @@ export default function App() {
     return (
       <>
         <StatusBar style={statusBarStyle} />
-        <LoadingScreen message="Loading..." />
+        <LoadingScreen message={t('common.loading', 'Loading...')} />
       </>
     );
   }
diff --git a/locales/rn/en.json b/locales/rn/en.json
index a0993041..c711f846 100644
--- a/locales/rn/en.json
+++ b/locales/rn/en.json
@@ -988,10 +988,11 @@
     "remove_account_hint": "Long-press to remove this account",
     "remove_account_message": "Sign out of {account} on this device. Your mail stays on the server.",
     "remove_account_title": "Remove account?",
-    "show_unread": "Show unread"
+    "show_unread": "Show unread",
+    "tab_unavailable": "{name} (unavailable)"
   },
   "unified_mailbox": {
-    "accounts_failed": "{count} account(s) could not be loaded"
+    "accounts_failed": "{count, plural, one {# account could not be loaded} other {# accounts could not be loaded}}"
   },
   "updates": {
     "advisory": "Security advisory",
diff --git a/scripts/harvest-rn-keys.mjs b/scripts/harvest-rn-keys.mjs
index c7875aaa..5c2853b5 100644
--- a/scripts/harvest-rn-keys.mjs
+++ b/scripts/harvest-rn-keys.mjs
@@ -68,7 +68,8 @@ const KEY_ONLY_RE = /\btr?\(\s*'([^']+)'/g;
 
 const added = [];
 const missingNoFallback = [];
-for (const file of walk(SRC)) {
+// App.tsx (the tab bar and loading screen) sits next to src/.
+for (const file of [...walk(SRC), join(ROOT, 'App.tsx')]) {
   const text = readFileSync(file, 'utf8');
   const withFallback = new Map();
   for (const m of text.matchAll(CALL_RE)) {
diff --git a/src/components/SidebarDrawer.tsx b/src/components/SidebarDrawer.tsx
index 528550bc..d207879f 100644
--- a/src/components/SidebarDrawer.tsx
+++ b/src/components/SidebarDrawer.tsx
@@ -166,6 +166,7 @@ function SidebarRow({
 }: SidebarRowProps) {
   const c = useColors();
   const styles = React.useMemo(() => makeStyles(c), [c]);
+  const t = useLocaleStore((s) => s.t);
   const leftPad = ROW_PX_BASE + depth * INDENT_STEP;
   return (
     <Pressable
@@ -184,6 +185,9 @@ function SidebarRow({
             onPress={onToggleExpand}
             hitSlop={6}
             style={styles.chevron}
+            accessibilityRole="button"
+            accessibilityLabel={isExpanded ? t('sidebar.collapse', 'Collapse') : t('sidebar.expand', 'Expand')}
+            accessibilityState={{ expanded: isExpanded }}
           >
             {isExpanded ? (
               <ChevronDown size={12} color={c.textMuted} />
@@ -758,7 +762,13 @@ export default function SidebarDrawer({ visible, onClose }: SidebarDrawerProps)
         <SafeAreaView style={styles.drawerSafe} edges={['top', 'bottom', 'left']}>
           {/* Header: close + account switcher */}
           <View style={styles.header}>
-            <Pressable onPress={onClose} style={styles.headerClose} hitSlop={8}>
+            <Pressable
+              onPress={onClose}
+              style={styles.headerClose}
+              hitSlop={8}
+              accessibilityRole="button"
+              accessibilityLabel={t('common.close', 'Close')}
+            >
               <X size={20} color={c.text} />
             </Pressable>
             <Pressable
@@ -860,7 +870,13 @@ export default function SidebarDrawer({ visible, onClose }: SidebarDrawerProps)
                         </View>
                       </View>
                       {!isActive && (
-                        <Pressable onPress={() => confirmRemoveAccount(acc)} hitSlop={8} style={styles.accountMenuRemove}>
+                        <Pressable
+                          onPress={() => confirmRemoveAccount(acc)}
+                          hitSlop={8}
+                          style={styles.accountMenuRemove}
+                          accessibilityRole="button"
+                          accessibilityLabel={t('sidebar.remove_account', 'Remove account')}
+                        >
                           <UserMinus size={14} color={c.textMuted} />
                         </Pressable>
                       )}
diff --git a/src/components/__tests__/screens-i18n.test.ts b/src/components/__tests__/screens-i18n.test.ts
index 3687d599..4be30f12 100644
--- a/src/components/__tests__/screens-i18n.test.ts
+++ b/src/components/__tests__/screens-i18n.test.ts
@@ -55,6 +55,10 @@ const TRANSLATED_FILES: Record<string, string[]> = {
   'components/email/QuickReplyBox.tsx': [],
   'components/email/AttachmentChips.tsx': [],
   'components/email/AttachmentPreviewModal.tsx': [],
+  'screens/UnifiedInboxScreen.tsx': [],
+  'components/SidebarDrawer.tsx': [],
+  // The app shell (tab bar, loading screen), next to src/.
+  '../App.tsx': [],
 };
 
 describe('translated screens', () => {
diff --git a/src/i18n/__tests__/keys.test.ts b/src/i18n/__tests__/keys.test.ts
index 08b515db..8cdfb389 100644
--- a/src/i18n/__tests__/keys.test.ts
+++ b/src/i18n/__tests__/keys.test.ts
@@ -21,6 +21,11 @@ function flatten(obj: Record<string, unknown>, prefix = '', out = new Set<string
   return out;
 }
 
+// src/ plus App.tsx next to it (the tab bar and loading screen).
+function sourceFiles(): string[] {
+  return [...walk(SRC_ROOT), join(SRC_ROOT, '..', 'App.tsx')];
+}
+
 function walk(dir: string, out: string[] = []): string[] {
   for (const entry of readdirSync(dir)) {
     const p = join(dir, entry);
@@ -48,7 +53,7 @@ describe('translation coverage', () => {
 
   it('every literal t() key in src exists in the English catalog', () => {
     const missing: string[] = [];
-    for (const file of walk(SRC_ROOT)) {
+    for (const file of sourceFiles()) {
       const text = readFileSync(file, 'utf8');
       for (const m of text.matchAll(LITERAL_KEY_RE)) {
         if (!en.has(m[1])) missing.push(`${m[1]}  (${relative(SRC_ROOT, file)})`);
@@ -59,7 +64,7 @@ describe('translation coverage', () => {
 
   it('every template t() key prefix has at least one English entry', () => {
     const missing: string[] = [];
-    for (const file of walk(SRC_ROOT)) {
+    for (const file of sourceFiles()) {
       const text = readFileSync(file, 'utf8');
       for (const m of text.matchAll(TEMPLATE_KEY_RE)) {
         const prefix = m[1];
diff --git a/src/screens/EmailListScreen.tsx b/src/screens/EmailListScreen.tsx
index 41e60310..969a31f1 100644
--- a/src/screens/EmailListScreen.tsx
+++ b/src/screens/EmailListScreen.tsx
@@ -1366,7 +1366,7 @@ export default function EmailListScreen({ onEmailPress, onComposePress }: EmailL
       {unreachedAccounts.length > 0 && (
         <View style={[styles.emptyFolderBanner, { borderColor: c.error }]}>
           <Text style={styles.emptyFolderHint} numberOfLines={2}>
-            {t('unified_mailbox.accounts_failed', `${unreachedAccounts.length} account(s) could not be loaded`, { count: unreachedAccounts.length })}
+            {t('unified_mailbox.accounts_failed', '{count, plural, one {# account could not be loaded} other {# accounts could not be loaded}}', { count: unreachedAccounts.length })}
             {`: ${unreachedAccounts[0]}`}
           </Text>
         </View>
diff --git a/src/screens/UnifiedInboxScreen.tsx b/src/screens/UnifiedInboxScreen.tsx
index a1e5cd41..a0d43f10 100644
--- a/src/screens/UnifiedInboxScreen.tsx
+++ b/src/screens/UnifiedInboxScreen.tsx
@@ -33,12 +33,12 @@ type Props = NativeStackScreenProps<RootStackParamList, 'UnifiedInbox'>;
 
 const PAGE_SIZE = 25;
 
-function senderName(email: UnifiedEmail, showRecipient: boolean): string {
+function senderName(email: UnifiedEmail, showRecipient: boolean, unknown: string): string {
   if (showRecipient) {
     const to = email.to?.[0];
     if (to) return to.name || to.email;
   }
-  return email.from?.[0]?.name || email.from?.[0]?.email || 'Unknown';
+  return email.from?.[0]?.name || email.from?.[0]?.email || unknown;
 }
 
 function rowKey(e: UnifiedEmail): string {
@@ -330,7 +330,7 @@ export default function UnifiedInboxScreen({ navigation, route }: Props) {
           )}
           <View style={styles.avatarWrap}>
             <SenderAvatar
-              name={senderName(item, showRecipient)}
+              name={senderName(item, showRecipient, t('email_viewer.unknown_sender', 'Unknown'))}
               email={showRecipient ? item.to?.[0]?.email : item.from?.[0]?.email}
               size={componentSizes.avatarMd}
               disableImages={role === 'junk' && !showAvatarsInJunk}
@@ -342,7 +342,7 @@ export default function UnifiedInboxScreen({ navigation, route }: Props) {
           <View style={styles.content}>
             <View style={styles.line}>
               <Text style={[styles.sender, unread && styles.bold]} numberOfLines={1}>
-                {senderName(item, showRecipient)}
+                {senderName(item, showRecipient, t('email_viewer.unknown_sender', 'Unknown'))}
               </Text>
               {starred && <Star size={12} color={c.starred} fill={c.starred} />}
               {item.hasAttachment && <Paperclip size={12} color={c.textMuted} />}
@@ -384,35 +384,79 @@ export default function UnifiedInboxScreen({ navigation, route }: Props) {
     <SafeAreaView style={styles.container} edges={['top']}>
       {selectionMode ? (
         <View style={styles.header}>
-          <Pressable onPress={clearSelection} style={styles.headerBtn} hitSlop={8}>
+          <Pressable
+            onPress={clearSelection}
+            style={styles.headerBtn}
+            hitSlop={8}
+            accessibilityRole="button"
+            accessibilityLabel={t('email_list.batch_actions.clear_selection', 'Clear selection')}
+          >
             <X size={20} color={c.text} />
           </Pressable>
           <Text style={styles.headerTitle} numberOfLines={1}>
-            {t('context_menu.items_selected', `${selected.size} selected`, { count: selected.size })}
+            {t('email_list.batch_actions.selected_messages', '{count, plural, one {1 email} other {# emails}} selected', { count: selected.size })}
           </Text>
-          <Pressable onPress={() => { setStarred(selectedEmails, !allStarred); clearSelection(); }} style={styles.headerBtn} hitSlop={6}>
+          <Pressable
+            onPress={() => { setStarred(selectedEmails, !allStarred); clearSelection(); }}
+            style={styles.headerBtn}
+            hitSlop={6}
+            accessibilityRole="button"
+            accessibilityLabel={allStarred ? t('context_menu.unstar', 'Unstar') : t('context_menu.star', 'Star')}
+          >
             <Star size={20} color={allStarred ? c.starred : c.text} fill={allStarred ? c.starred : 'transparent'} />
           </Pressable>
-          <Pressable onPress={() => { setRead(selectedEmails, !allRead); clearSelection(); }} style={styles.headerBtn} hitSlop={6}>
+          <Pressable
+            onPress={() => { setRead(selectedEmails, !allRead); clearSelection(); }}
+            style={styles.headerBtn}
+            hitSlop={6}
+            accessibilityRole="button"
+            accessibilityLabel={allRead
+              ? t('email_list.batch_actions.mark_unread', 'Mark as unread')
+              : t('email_list.batch_actions.mark_read', 'Mark as read')}
+          >
             {allRead ? <MailIcon size={20} color={c.text} /> : <MailOpen size={20} color={c.text} />}
           </Pressable>
           {role !== 'sent' && role !== 'drafts' && (
-            <Pressable onPress={() => { spam(selectedEmails); clearSelection(); }} style={styles.headerBtn} hitSlop={6}>
+            <Pressable
+              onPress={() => { spam(selectedEmails); clearSelection(); }}
+              style={styles.headerBtn}
+              hitSlop={6}
+              accessibilityRole="button"
+              accessibilityLabel={role === 'junk' ? t('context_menu.not_spam', 'Not spam') : t('context_menu.mark_as_spam', 'Report spam')}
+            >
               {role === 'junk' ? <ShieldCheck size={20} color={c.text} /> : <ShieldAlert size={20} color={c.text} />}
             </Pressable>
           )}
           {role !== 'archive' && (
-            <Pressable onPress={() => { archive(selectedEmails); clearSelection(); }} style={styles.headerBtn} hitSlop={6}>
+            <Pressable
+              onPress={() => { archive(selectedEmails); clearSelection(); }}
+              style={styles.headerBtn}
+              hitSlop={6}
+              accessibilityRole="button"
+              accessibilityLabel={t('context_menu.archive', 'Archive')}
+            >
               <Archive size={20} color={c.text} />
             </Pressable>
           )}
-          <Pressable onPress={() => { void remove(selectedEmails).then(clearSelection); }} style={styles.headerBtn} hitSlop={6}>
+          <Pressable
+            onPress={() => { void remove(selectedEmails).then(clearSelection); }}
+            style={styles.headerBtn}
+            hitSlop={6}
+            accessibilityRole="button"
+            accessibilityLabel={t('email_list.batch_actions.delete', 'Delete')}
+          >
             <Trash2 size={20} color={c.text} />
           </Pressable>
         </View>
       ) : (
         <View style={styles.header}>
-          <Pressable onPress={() => navigation.goBack()} style={styles.headerBtn} hitSlop={8}>
+          <Pressable
+            onPress={() => navigation.goBack()}
+            style={styles.headerBtn}
+            hitSlop={8}
+            accessibilityRole="button"
+            accessibilityLabel={t('common.back', 'Back')}
+          >
             <ArrowLeft size={22} color={c.text} />
           </Pressable>
           <Text style={styles.headerTitle} numberOfLines={1}>{title}</Text>
@@ -436,7 +480,12 @@ export default function UnifiedInboxScreen({ navigation, route }: Props) {
           returnKeyType="search"
         />
         {searchInput.length > 0 && (
-          <Pressable onPress={() => { setSearchInput(''); setQuery(''); }} hitSlop={8}>
+          <Pressable
+            onPress={() => { setSearchInput(''); setQuery(''); }}
+            hitSlop={8}
+            accessibilityRole="button"
+            accessibilityLabel={t('contacts.clear_search', 'Clear search')}
+          >
             <X size={14} color={c.textMuted} />
           </Pressable>
         )}
@@ -446,7 +495,7 @@ export default function UnifiedInboxScreen({ navigation, route }: Props) {
         <View style={styles.errorBanner}>
           <AlertTriangle size={14} color={c.error} />
           <Text style={styles.errorBannerText} numberOfLines={2}>
-            {t('unified_mailbox.accounts_failed', `${errorCount} account(s) could not be loaded`, { count: errorCount })}
+            {t('unified_mailbox.accounts_failed', '{count, plural, one {# account could not be loaded} other {# accounts could not be loaded}}', { count: errorCount })}
             {': '}
             {Object.values(errors)[0]}
           </Text>