diff --git a/core/lib/Controllers/InitController.php b/core/lib/Controllers/InitController.php
index 3f375a4..6de2b1f 100644
--- a/core/lib/Controllers/InitController.php
+++ b/core/lib/Controllers/InitController.php
@@ -2,14 +2,15 @@
 
 namespace KTXC\Controllers;
 
+use KTXC\Http\Request\Request;
 use KTXC\Http\Response\JsonResponse;
+use KTXC\L10N\LocaleResolver;
 use KTXC\Module\ModuleManager;
 use KTXC\Security\Authorization\PermissionChecker;
 use KTXC\Service\UserAccountsService;
 use KTXC\SessionIdentity;
 use KTXF\Controller\ControllerAbstract;
 use KTXC\SessionTenant;
-use KTXF\Module\ModuleBrowserInterface;
 use KTXF\Routing\Attributes\AuthenticatedRoute;
 
 class InitController extends ControllerAbstract
@@ -20,10 +21,11 @@ class InitController extends ControllerAbstract
         private readonly ModuleManager $moduleManager,
         private readonly UserAccountsService $userService,
         private readonly PermissionChecker $permissionChecker,
+        private readonly LocaleResolver $localeResolver,
     ) {}
 
     #[AuthenticatedRoute('/init', name: 'init', methods: ['GET'])]
-    public function index(): JsonResponse {
+    public function index(Request $request): JsonResponse {
         
         $configuration = [];
 
@@ -43,6 +45,13 @@ class InitController extends ControllerAbstract
             }
         }
 
+        // localization
+        $configuration['l10n'] = [
+            'locale' => $this->localeResolver->resolve($request),
+            'fallback' => LocaleResolver::FALLBACK,
+            'available' => $this->localeResolver->available(),
+        ];
+
         // tenant
         $configuration['tenant'] = [
             'id' => $this->tenant->identifier(),
diff --git a/core/lib/L10N/LocaleResolver.php b/core/lib/L10N/LocaleResolver.php
new file mode 100644
index 0000000..492c5cd
--- /dev/null
+++ b/core/lib/L10N/LocaleResolver.php
@@ -0,0 +1,71 @@
+<?php
+
+namespace KTXC\L10N;
+
+use DI\Attribute\Inject;
+use KTXC\Http\Request\Request;
+use KTXC\Service\UserAccountsService;
+
+/**
+ * Resolves the effective UI locale for the current user.
+ *
+ * Resolution chain: user setting (core.locale) -> Accept-Language
+ * negotiation -> fallback. Tenant default slots in between once tenant
+ * settings expose one (Phase 3).
+ */
+class LocaleResolver
+{
+    public const FALLBACK = 'en';
+    public const SETTING_KEY = 'core.locale';
+
+    public function __construct(
+        private readonly UserAccountsService $userService,
+        #[Inject('rootDir')] private readonly string $rootDir,
+    ) {}
+
+    /**
+     * Locales with a core catalog on disk (public/l10n/*.json), always
+     * including the fallback. This backs the language picker, so a locale
+     * is only offered when it has at least core-shell coverage.
+     *
+     * @return string[]
+     */
+    public function available(): array
+    {
+        $locales = [self::FALLBACK];
+        foreach (glob($this->rootDir . '/public/l10n/*.json') ?: [] as $file) {
+            $locales[] = basename($file, '.json');
+        }
+        $locales = array_values(array_unique($locales));
+        sort($locales);
+        return $locales;
+    }
+
+    public function resolve(Request $request): string
+    {
+        $available = $this->available();
+
+        // 1. explicit user preference
+        $settings = $this->userService->fetchSettings([self::SETTING_KEY]);
+        $preference = $settings[self::SETTING_KEY] ?? null;
+        if (is_string($preference) && in_array($preference, $available, true)) {
+            return $preference;
+        }
+
+        // 2. Accept-Language negotiation. getPreferredLanguage() returns the
+        // first candidate when nothing matches, so the fallback leads the
+        // list; it also normalizes to underscore form (pt_BR) while catalogs
+        // use BCP-47 hyphens.
+        $candidates = array_merge([self::FALLBACK], array_diff($available, [self::FALLBACK]));
+        $negotiated = $request->getPreferredLanguage($candidates);
+        if ($negotiated !== null) {
+            $negotiated = str_replace('_', '-', $negotiated);
+            if (in_array($negotiated, $available, true)) {
+                return $negotiated;
+            }
+        }
+
+        // 3. fallback
+        return self::FALLBACK;
+    }
+}
diff --git a/core/src/composables/index.ts b/core/src/composables/index.ts
index 700784e..5a99236 100644
--- a/core/src/composables/index.ts
+++ b/core/src/composables/index.ts
@@ -3,4 +3,6 @@
  */
 
 export { useClipboard } from './useClipboard'
+export { useL10n, t } from './useL10n'
+export type { L10N, TranslateParams } from './useL10n'
 export { useUser } from './useUser'
diff --git a/core/src/composables/useL10n.ts b/core/src/composables/useL10n.ts
new file mode 100644
index 0000000..1396751
--- /dev/null
+++ b/core/src/composables/useL10n.ts
@@ -0,0 +1,42 @@
+/**
+ * Translation composable over the shared i18n runtime.
+ * This is the only surface components and modules use; vue-i18n itself
+ * stays confined to the plugin.
+ */
+import { i18n } from '@KTXC/l10n/runtime';
+
+export type TranslateParams = Record<string, unknown>;
+
+export interface L10N {
+  /**
+   * Translate a catalog key, rendering the inline English default when the
+   * key is absent from every loaded catalog. Keys are namespaced with the
+   * handle bound at useL10n(); the `en` catalog is generated from these
+   * defaults by scripts/l10n-extract.mjs — keep both literal.
+   */
+  t: (key: string, defaultText: string, params?: TranslateParams) => string;
+  /** Locale-aware date/time formatting (Intl-backed). */
+  d: typeof i18n.global.d;
+  /** Locale-aware number formatting (Intl-backed). */
+  n: typeof i18n.global.n;
+}
+
+/**
+ * Translate a fully-qualified catalog key (one that already carries its
+ * namespace, e.g. an integration entry's `l10n` key, which the integration
+ * store prefixes with the module handle). `defaultText` is rendered when the
+ * key is undefined or absent from every loaded catalog. Such keys are
+ * dynamic, so their catalog entries live in the module's hand-maintained
+ * en.manual.json rather than the extracted catalog.
+ */
+export function t(key: string | undefined, defaultText?: string, params: TranslateParams = {}): string {
+  if (!key) return defaultText ?? '';
+  return i18n.global.t(key, params, { default: defaultText ?? key });
+}
+
+export function useL10n(namespace: string): L10N {
+  const scoped = (key: string, defaultText: string, params: TranslateParams = {}): string =>
+    t(`${namespace}.${key}`, defaultText, params);
+
+  return { t: scoped, d: i18n.global.d, n: i18n.global.n };
+}
diff --git a/core/src/l10n/de.json b/core/src/l10n/de.json
new file mode 100644
index 0000000..0058712
--- /dev/null
+++ b/core/src/l10n/de.json
@@ -0,0 +1,24 @@
+{
+  "header": {
+    "searchPlaceholder": "Hier suchen.."
+  },
+  "systemMenu": {
+    "administration": "Administration",
+    "applications": "Anwendungen",
+    "personalSettings": "Persönliche Einstellungen",
+    "toggleAdmin": "Admin",
+    "toggleApps": "Apps",
+    "toggleSettings": "Einstellungen"
+  },
+  "notifications": {
+    "markAllRead": "Alle als gelesen markieren",
+    "title": "Benachrichtigungen",
+    "viewAll": "Alle anzeigen"
+  },
+  "userMenu": {
+    "darkMode": "Dunkles Design",
+    "lightMode": "Helles Design",
+    "logout": "Abmelden",
+    "settings": "Einstellungen"
+  }
+}
diff --git a/core/src/l10n/en.json b/core/src/l10n/en.json
new file mode 100644
index 0000000..8158294
--- /dev/null
+++ b/core/src/l10n/en.json
@@ -0,0 +1,14 @@
+{
+  "systemMenu": {
+    "adminSettings": "System",
+    "apps": "Applications",
+    "personalSettings": "Settings",
+    "userSettings": "Settings"
+  },
+  "userMenu": {
+    "darkMode": "Dark Mode",
+    "lightMode": "Light Mode",
+    "logout": "Logout",
+    "settings": "Settings"
+  }
+}
diff --git a/core/src/l10n/runtime.ts b/core/src/l10n/runtime.ts
new file mode 100644
index 0000000..2a002bc
--- /dev/null
+++ b/core/src/l10n/runtime.ts
@@ -0,0 +1,33 @@
+import { createI18n } from 'vue-i18n';
+import { en as vuetifyEn, de as vuetifyDe } from 'vuetify/locale';
+
+export const FALLBACK_LOCALE = 'en';
+
+/**
+ * The single vue-i18n instance shared by the core shell and all modules.
+ */
+export const i18n = createI18n({
+  legacy: false,
+  globalInjection: false,
+  locale: FALLBACK_LOCALE,
+  fallbackLocale: FALLBACK_LOCALE,
+  missingWarn: import.meta.env.DEV,
+  fallbackWarn: false,
+  messages: {
+    // Vuetify component strings ($vuetify.*) ride along in the same
+    // instance, consumed through the createVueI18nAdapter in the vuetify
+    // plugin. Statically imported: adding a locale means adding it here.
+    en: { $vuetify: vuetifyEn },
+    de: { $vuetify: vuetifyDe },
+  },
+});
+
+/** Merge a catalog's messages under a namespace for the given locale. */
+export function mergeCatalog(locale: string, namespace: string, messages: Record<string, unknown>): void {
+  i18n.global.mergeLocaleMessage(locale, { [namespace]: messages });
+}
+
+/** Switch the active locale of the shared instance. */
+export function applyLocale(locale: string): void {
+  i18n.global.locale.value = locale;
+}
diff --git a/core/src/layouts/menus/LayoutSystemMenu.vue b/core/src/layouts/menus/LayoutSystemMenu.vue
index d71ea8a..c7a6a58 100644
--- a/core/src/layouts/menus/LayoutSystemMenu.vue
+++ b/core/src/layouts/menus/LayoutSystemMenu.vue
@@ -2,6 +2,7 @@
 import { computed } from 'vue';
 import { useLayoutStore } from '@KTXC/stores/layoutStore';
 import { useIntegrationStore } from '@KTXC/stores/integrationStore';
+import { useL10n } from '@KTXC/composables/useL10n';
 import Logo from '@KTXC/layouts/logo/LogoDark.vue';
 import SystemMenuGroupStatic from './LayoutSystemMenuGroupStatic.vue';
 import SystemMenuGroupDynamic from './LayoutSystemMenuGroupDynamic.vue';
@@ -9,6 +10,7 @@ import SystemMenuItem from './LayoutSystemMenuItem.vue';
 
 const layoutStore = useLayoutStore();
 const integrationStore = useIntegrationStore();
+const { t } = useL10n('core');
 
 // Get all entries based on current menu mode
 const menuEntries = computed(() => {
@@ -29,23 +31,23 @@ const menuModeInfo = computed(() => {
     case 'user-settings':
       return {
         icon: 'mdi-account-cog',
-        label: 'Personal Settings',
-        toggleLabel: 'Admin',
+        label: t('systemMenu.personalSettings', 'Settings'),
+        toggleLabel: t('systemMenu.adminSettings', 'System'),
         toggleIcon: 'mdi-shield-crown',
       };
     case 'admin-settings':
       return {
         icon: 'mdi-shield-crown',
-        label: 'Administration',
-        toggleLabel: 'Apps',
+        label: t('systemMenu.adminSettings', 'System'),
+        toggleLabel: t('systemMenu.apps', 'Applications'),
         toggleIcon: 'mdi-view-dashboard',
       };
     case 'apps':
     default:
       return {
         icon: 'mdi-view-dashboard',
-        label: 'Applications',
-        toggleLabel: 'Settings',
+        label: t('systemMenu.apps', 'Applications'),
+        toggleLabel: t('systemMenu.userSettings', 'Settings'),
         toggleIcon: 'mdi-account-cog',
       };
   }
diff --git a/core/src/layouts/menus/LayoutSystemMenuGroupDynamic.vue b/core/src/layouts/menus/LayoutSystemMenuGroupDynamic.vue
index af1dc4c..81170f5 100644
--- a/core/src/layouts/menus/LayoutSystemMenuGroupDynamic.vue
+++ b/core/src/layouts/menus/LayoutSystemMenuGroupDynamic.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import type { IntegrationGroup } from '@KTXC/types/integrationTypes';
+import { t } from '@KTXC/composables/useL10n';
 import NavItem from './LayoutSystemMenuItem.vue';
 
 const props = defineProps<{ group: IntegrationGroup; level?: number }>();
@@ -20,7 +21,7 @@ const props = defineProps<{ group: IntegrationGroup; level?: number }>();
           <v-icon v-if="group.icon" :icon="group.icon"></v-icon>
         </template>
         <!---Title  -->
-        <v-list-item-title class="mr-auto">{{ group.label }}</v-list-item-title>
+        <v-list-item-title class="mr-auto">{{ t(group.l10n, group.label) }}</v-list-item-title>
         <!---If Caption-->
         <v-list-item-subtitle v-if="group.caption" class="text-caption mt-n1 hide-menu">
           {{ group.caption }}
diff --git a/core/src/layouts/menus/LayoutSystemMenuGroupStatic.vue b/core/src/layouts/menus/LayoutSystemMenuGroupStatic.vue
index 86518a9..006830f 100644
--- a/core/src/layouts/menus/LayoutSystemMenuGroupStatic.vue
+++ b/core/src/layouts/menus/LayoutSystemMenuGroupStatic.vue
@@ -1,12 +1,13 @@
 <script setup lang="ts">
 import type { IntegrationGroup } from '@KTXC/types/integrationTypes';
+import { t } from '@KTXC/composables/useL10n';
 import LayoutSystemMenuItem from './LayoutSystemMenuItem.vue';
 
 const props = defineProps<{ group: IntegrationGroup }>();
 </script>
 
 <template>
-  <v-list-subheader color="lightText" class="smallCap text-subtitle-2">{{ props.group.label }}</v-list-subheader>
+  <v-list-subheader color="lightText" class="smallCap text-subtitle-2">{{ t(props.group.l10n, props.group.label) }}</v-list-subheader>
   <LayoutSystemMenuItem
     v-for="(item, i) in props.group.items"
     :key="i"
diff --git a/core/src/layouts/menus/LayoutSystemMenuItem.vue b/core/src/layouts/menus/LayoutSystemMenuItem.vue
index a02ed6f..6a10d1c 100644
--- a/core/src/layouts/menus/LayoutSystemMenuItem.vue
+++ b/core/src/layouts/menus/LayoutSystemMenuItem.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import type { IntegrationItem } from '@KTXC/types/integrationTypes';
+import { t } from '@KTXC/composables/useL10n';
 
 const props = defineProps<{ item: IntegrationItem; level?: number }>();
 </script>
@@ -20,7 +21,7 @@ const props = defineProps<{ item: IntegrationItem; level?: number }>();
     <template v-slot:prepend>
       <v-icon v-if="props.item.icon" :icon="props.item.icon"></v-icon>
     </template>
-    <v-list-item-title>{{ item.label }}</v-list-item-title>
+    <v-list-item-title>{{ t(item.l10n, item.label) }}</v-list-item-title>
     <!---If Caption-->
     <v-list-item-subtitle v-if="item.caption" class="text-caption mt-n1 hide-menu">
       {{ item.caption }}
diff --git a/core/src/layouts/menus/LayoutUserMenu.vue b/core/src/layouts/menus/LayoutUserMenu.vue
index 458bd83..300b966 100644
--- a/core/src/layouts/menus/LayoutUserMenu.vue
+++ b/core/src/layouts/menus/LayoutUserMenu.vue
@@ -5,8 +5,11 @@ import { useUserStore } from '@KTXC/stores/userStore';
 import { useIntegrationStore } from '@KTXC/stores/integrationStore';
 import { useLayoutStore } from '@KTXC/stores/layoutStore';
 import { useRouter } from 'vue-router';
+import { useL10n, t as tGlobal } from '@KTXC/composables/useL10n';
 import defaultAvatar from '@KTXC/assets/images/users/avatar-1.png';
 
+const { t } = useL10n('core');
+
 const theme = useTheme();
 const router = useRouter();
 const userStore = useUserStore();
@@ -74,7 +77,7 @@ const goToSettings = () => {
           <template v-slot:prepend>
             <v-icon v-if="item.icon">{{ item.icon }}</v-icon>
           </template>
-          <v-list-item-title class="text-h6">{{ item.label }}</v-list-item-title>
+          <v-list-item-title class="text-h6">{{ tGlobal(item.l10n, item.label) }}</v-list-item-title>
         </v-list-item>
 
         <v-divider v-if="profileMenuItems.length" class="my-2" />
@@ -84,7 +87,7 @@ const goToSettings = () => {
           <template v-slot:prepend>
             <v-icon>{{ isDarkMode ? 'mdi-weather-sunny' : 'mdi-weather-night' }}</v-icon>
           </template>
-          <v-list-item-title class="text-h6">{{ isDarkMode ? 'Light Mode' : 'Dark Mode' }}</v-list-item-title>
+          <v-list-item-title class="text-h6">{{ isDarkMode ? t('userMenu.lightMode', 'Light Mode') : t('userMenu.darkMode', 'Dark Mode') }}</v-list-item-title>
         </v-list-item>
 
         <!-- Go to Settings -->
@@ -92,7 +95,7 @@ const goToSettings = () => {
           <template v-slot:prepend>
             <v-icon>mdi-cog-outline</v-icon>
           </template>
-          <v-list-item-title class="text-h6">Settings</v-list-item-title>
+          <v-list-item-title class="text-h6">{{ t('userMenu.settings', 'Settings') }}</v-list-item-title>
         </v-list-item>
 
         <v-divider class="my-2" />
@@ -102,7 +105,7 @@ const goToSettings = () => {
           <template v-slot:prepend>
             <v-icon>mdi-logout</v-icon>
           </template>
-          <v-list-item-title class="text-h6">Logout</v-list-item-title>
+          <v-list-item-title class="text-h6">{{ t('userMenu.logout', 'Logout') }}</v-list-item-title>
         </v-list-item>
       </v-list>
     </perfect-scrollbar>
diff --git a/core/src/plugins/vuetify/index.ts b/core/src/plugins/vuetify/index.ts
index 2dcf8b5..c44407b 100644
--- a/core/src/plugins/vuetify/index.ts
+++ b/core/src/plugins/vuetify/index.ts
@@ -2,6 +2,9 @@ import { createVuetify } from 'vuetify'
 import { VBtn } from 'vuetify/components/VBtn'
 import * as components from 'vuetify/components'
 import * as directives from 'vuetify/directives'
+import { createVueI18nAdapter } from 'vuetify/locale/adapters/vue-i18n'
+import { useI18n } from 'vue-i18n'
+import { i18n } from '@KTXC/l10n/runtime'
 import defaults from './defaults'
 import { icons } from './icons'
 import { themes } from './theme'
@@ -17,6 +20,9 @@ export default createVuetify({
   },
   defaults,
   icons,
+  locale: {
+    adapter: createVueI18nAdapter({ i18n, useI18n }),
+  },
   theme: {
     defaultTheme: 'light',
     themes,
diff --git a/core/src/private.ts b/core/src/private.ts
index 2a7153b..44c4a4b 100644
--- a/core/src/private.ts
+++ b/core/src/private.ts
@@ -7,6 +7,8 @@ import { PerfectScrollbarPlugin } from 'vue3-perfect-scrollbar'
 import { useModuleStore } from '@KTXC/stores/moduleStore'
 import { useTenantStore } from '@KTXC/stores/tenantStore'
 import { useUserStore } from '@KTXC/stores/userStore'
+import { useL10nStore } from '@KTXC/stores/l10nStore'
+import { i18n } from '@KTXC/l10n/runtime'
 import { fetchWrapper } from '@KTXC/utils/helpers/fetch-wrapper'
 import { FetchError } from '@KTXC/utils/helpers/fetch-wrapper-core'
 import { initializeModules } from '@KTXC/utils/modules'
@@ -22,6 +24,7 @@ const app = createApp(App)
 const pinia = createPinia()
 app.use(pinia)
 app.use(PerfectScrollbarPlugin)
+app.use(i18n)
 app.use(vuetify)
 
 const globalWindow = window as typeof window & {
@@ -37,13 +40,17 @@ globalWindow.Pinia = PiniaLib as unknown
 	const moduleStore = useModuleStore();
 	const tenantStore = useTenantStore();
 	const userStore = useUserStore();
-	
+	const l10nStore = useL10nStore();
+
 	try {
 		const payload = await fetchWrapper.get('/init');
 		moduleStore.init(payload?.modules ?? {});
 		tenantStore.init(payload?.tenant ?? null);
 		userStore.init(payload?.user ?? {});
 
+		// Resolve locale and load catalogs before modules boot
+		await l10nStore.init(payload?.l10n ?? null);
+
 		// Initialize auth session monitor
 		const sessionMonitor = createSessionMonitor({ onLogout: () => userStore.logout() });
 		sessionMonitor.start();
diff --git a/core/src/public.ts b/core/src/public.ts
index 059f16f..091e451 100644
--- a/core/src/public.ts
+++ b/core/src/public.ts
@@ -3,6 +3,8 @@ import { createPinia } from 'pinia';
 import App from './App.vue';
 import { router } from './router';
 import { AUTH_STORAGE_KEY } from '@KTXC/stores/userStore';
+import { useL10nStore } from '@KTXC/stores/l10nStore';
+import { i18n } from '@KTXC/l10n/runtime';
 import vuetify from './plugins/vuetify/index';
 
 // Material Design Icons (Vuetify mdi icon set)
@@ -19,6 +21,11 @@ const app = createApp(App);
 const pinia = createPinia();
 app.use(pinia);
 app.use(router);
+app.use(i18n);
 app.use(vuetify);
 
-app.mount('#app');
+(async () => {
+	// No session yet: locale comes from browser preferences alone
+	await useL10nStore().init(null);
+	app.mount('#app');
+})();
diff --git a/core/src/shared/index.ts b/core/src/shared/index.ts
index 6df6a8d..11888f7 100644
--- a/core/src/shared/index.ts
+++ b/core/src/shared/index.ts
@@ -12,8 +12,11 @@ export { useTenantStore } from '../stores/tenantStore'
 export { useUserStore } from '../stores/userStore'
 export { useIntegrationStore } from '../stores/integrationStore'
 export { useLayoutStore } from '../stores/layoutStore'
+export { useL10nStore } from '../stores/l10nStore'
 
 // Composables
+export { useL10n, t } from '../composables/useL10n'
+export type { L10N, TranslateParams } from '../composables/useL10n'
 export { useUser } from '../composables/useUser'
 export { useClipboard } from '../composables/useClipboard'
 export { useSnackbar } from '../composables/useSnackbar'
diff --git a/core/src/stores/integrationStore.ts b/core/src/stores/integrationStore.ts
index f2d3c59..ffca17f 100644
--- a/core/src/stores/integrationStore.ts
+++ b/core/src/stores/integrationStore.ts
@@ -65,6 +65,11 @@ export const useIntegrationStore = defineStore('integrationStore', {
       // Remove 'type' field as it's only used for module-side disambiguation
       delete prefixed.type;
 
+      // Prefix localization keys with the module namespace
+      if (entry.l10n) {
+        prefixed.l10n = `${moduleHandle}.${entry.l10n}`;
+      }
+
       // Prefix internal paths
       if (entry.path) {
         prefixed.to = `/m/${moduleHandle}${entry.path}`;
diff --git a/core/src/stores/l10nStore.ts b/core/src/stores/l10nStore.ts
new file mode 100644
index 0000000..7e12815
--- /dev/null
+++ b/core/src/stores/l10nStore.ts
@@ -0,0 +1,151 @@
+import { defineStore } from 'pinia';
+import { ref, computed } from 'vue';
+import { FALLBACK_LOCALE, mergeCatalog, applyLocale } from '@KTXC/l10n/runtime';
+import { useUserStore } from '@KTXC/stores/userStore';
+
+const CORE_NAMESPACE = 'core';
+const SETTING_KEY = 'core.locale';
+const RTL_LANGUAGES = ['ar', 'fa', 'he', 'ur'];
+
+export type CatalogMessages = Record<string, unknown>;
+export type CatalogProvider = (locale: string) => Promise<CatalogMessages | null>;
+
+export interface L10nInitPayload {
+  locale?: string;
+  fallback?: string;
+  available?: string[];
+}
+
+export const useL10nStore = defineStore('l10nStore', () => {
+  const locale = ref(FALLBACK_LOCALE);
+  const available = ref<string[]>([FALLBACK_LOCALE]);
+
+  const isRtl = computed(() => RTL_LANGUAGES.includes(locale.value.split('-')[0]));
+
+  // Catalog providers know where their namespace's messages come from. The
+  // store only coordinates them as the active locale changes.
+  const catalogProviders = new Map<string, CatalogProvider>([
+    [CORE_NAMESPACE, async (target: string) => {
+      const response = await fetch(`/l10n/${target}.json`, {
+        headers: { Accept: 'application/json' },
+      });
+      return response.ok ? await response.json() : null;
+    }],
+  ]);
+
+  // catalog fetch results per "namespace:locale": true = merged, false = not on server
+  const catalogState = new Map<string, boolean>();
+
+  async function loadCatalog(namespace: string, target: string): Promise<boolean> {
+    const cacheKey = `${namespace}:${target}`;
+    const known = catalogState.get(cacheKey);
+    if (known !== undefined) return known;
+    const provider = catalogProviders.get(namespace);
+    if (!provider) return false;
+    try {
+      const messages = await provider(target);
+      if (!messages) {
+        catalogState.set(cacheKey, false);
+        return false;
+      }
+      mergeCatalog(target, namespace, messages);
+      catalogState.set(cacheKey, true);
+      return true;
+    } catch (error) {
+      // network error: leave state unset so a later attempt can retry
+      console.warn(`L10N - Failed to load ${namespace} catalog for ${target}:`, error);
+      return false;
+    }
+  }
+
+  async function loadCoreCatalog(target: string): Promise<boolean> {
+    return loadCatalog(CORE_NAMESPACE, target);
+  }
+
+  /** Load every registered namespace (core + modules) for a locale. */
+  async function loadCatalogs(target: string): Promise<void> {
+    await Promise.all(
+      [...catalogProviders.keys()].map((namespace) => loadCatalog(namespace, target)),
+    );
+  }
+
+  /**
+   * Register a namespace-specific catalog provider. The caller owns catalog
+   * discovery and transport; this store owns locale orchestration and merging.
+   */
+  async function registerCatalogProvider(namespace: string, provider: CatalogProvider): Promise<void> {
+    catalogProviders.set(namespace, provider);
+    for (const cacheKey of catalogState.keys()) {
+      if (cacheKey.startsWith(`${namespace}:`)) catalogState.delete(cacheKey);
+    }
+    await loadCatalog(namespace, FALLBACK_LOCALE);
+    if (locale.value !== FALLBACK_LOCALE) {
+      await loadCatalog(namespace, locale.value);
+    }
+  }
+
+  async function activate(target: string): Promise<void> {
+    await loadCatalogs(FALLBACK_LOCALE);
+    if (target !== FALLBACK_LOCALE) {
+      await loadCatalogs(target);
+    }
+    locale.value = target;
+    applyLocale(target);
+    document.documentElement.setAttribute('lang', target);
+    document.documentElement.setAttribute('dir', isRtl.value ? 'rtl' : 'ltr');
+  }
+
+  /**
+   * Locale candidates from browser preferences: each tag plus its base
+   * language, in preference order ('de-AT' -> 'de-AT', 'de').
+   */
+  function browserCandidates(): string[] {
+    const candidates: string[] = [];
+    for (const tag of navigator.languages ?? [navigator.language]) {
+      if (!tag) continue;
+      const base = tag.split('-')[0];
+      if (!candidates.includes(tag)) candidates.push(tag);
+      if (!candidates.includes(base)) candidates.push(base);
+    }
+    return candidates;
+  }
+
+  /**
+   * Bootstrap from the /init l10n block (private shell), or from browser
+   * preferences alone when there is no session (public shell).
+   */
+  async function init(payload?: L10nInitPayload | null): Promise<void> {
+    if (payload?.available?.length) {
+      available.value = payload.available;
+    }
+    if (payload?.locale) {
+      await activate(payload.locale);
+      return;
+    }
+    // No resolved locale: probe browser candidates against served catalogs
+    for (const candidate of browserCandidates()) {
+      if (candidate === FALLBACK_LOCALE || (await loadCoreCatalog(candidate))) {
+        await activate(candidate);
+        return;
+      }
+    }
+    await activate(FALLBACK_LOCALE);
+  }
+
+  /** Switch locale; persists as the user's `core.locale` setting by default. */
+  async function setLocale(target: string, persist = true): Promise<void> {
+    await activate(target);
+    if (persist) {
+      useUserStore().setSetting(SETTING_KEY, target);
+    }
+  }
+
+  return {
+    locale,
+    available,
+    isRtl,
+    init,
+    setLocale,
+    registerCatalogProvider,
+  };
+});
diff --git a/core/src/types/integrationTypes.ts b/core/src/types/integrationTypes.ts
index fbdf0c3..ab589c7 100644
--- a/core/src/types/integrationTypes.ts
+++ b/core/src/types/integrationTypes.ts
@@ -13,6 +13,8 @@ export interface IntegrationItem {
   moduleHandle: string;
   priority?: number;
   label?: string;
+  /** Localization key for the label (module-relative; prefixed with the handle on registration). `label` is its fallback. */
+  l10n?: string;
   caption?: string;
   icon?: string;
   to?: string;
@@ -30,6 +32,8 @@ export interface IntegrationGroup {
   moduleHandle: string;
   priority?: number;
   label?: string;
+  /** Localization key for the label (module-relative; prefixed with the handle on registration). `label` is its fallback. */
+  l10n?: string;
   caption?: string;
   icon?: string;
   style?: IntegrationGroupStyle;
diff --git a/core/src/utils/modules.ts b/core/src/utils/modules.ts
index 5bcaa19..2c708a3 100644
--- a/core/src/utils/modules.ts
+++ b/core/src/utils/modules.ts
@@ -2,6 +2,8 @@ import type { App } from 'vue';
 import { router } from '@KTXC/router';
 import { useModuleStore } from '@KTXC/stores/moduleStore';
 import { useIntegrationStore } from '@KTXC/stores/integrationStore';
+import { useL10nStore } from '@KTXC/stores/l10nStore';
+import type { CatalogMessages } from '@KTXC/stores/l10nStore';
 
 function installModuleCSS(moduleHandle: string, cssPaths: string | string[]): void {
   const cssFiles = Array.isArray(cssPaths) ? cssPaths : [cssPaths];
@@ -46,12 +48,20 @@ function installModuleRoutes(moduleHandle: string, routes: any[]): void {
   });
 }
 
-function installModuleIntegrations(
-  moduleHandle: string,
-  integrations: Record<string, any[]>
-): void {
-  const integrationStore = useIntegrationStore();
-  integrationStore.registerModuleIntegrations(moduleHandle, integrations);
+function installModuleIntegrations(moduleHandle: string, integrations: Record<string, any[]>): void {
+  useIntegrationStore().registerModuleIntegrations(moduleHandle, integrations);
+}
+
+async function installModuleLocalizations(moduleHandle: string): Promise<void> {
+  await useL10nStore().registerCatalogProvider(moduleHandle, (locale) => loadModuleLocalizations(moduleHandle, locale));
+}
+
+async function loadModuleLocalizations(moduleHandle: string, locale: string): Promise<CatalogMessages | null> {
+  const response = await fetch(
+    `/modules/${moduleHandle}/static/l10n/${locale}.json`,
+    { headers: { Accept: 'application/json' } },
+  );
+  return response.ok ? await response.json() : null;
 }
 
 export async function initializeModules(app: App): Promise<void> {
@@ -72,11 +82,16 @@ export async function initializeModules(app: App): Promise<void> {
       console.log(`Module Loader - Loading ${moduleInfo.handle} from ${moduleUrl}`);
 
       const loadPromise = import(/* @vite-ignore */ moduleUrl)
-        .then((module) => {
+        .then(async (module) => {
           // Load CSS if module explicitly exports css path(s)
           if (module.css) {
             installModuleCSS(moduleInfo.handle, module.css);
           }
+          // Load translation catalogs if module explicitly exports l10n flag
+          if (module.l10n) {
+            console.log(`Module Loader - Installing Catalogs ${moduleInfo.handle}`);
+            await installModuleLocalizations(moduleHandle);
+          }
           // install module
           console.log(`Module Loader - Installing ${moduleInfo.handle}`);
           if (module.default && typeof module.default.install === 'function') {
@@ -104,4 +119,4 @@ export async function initializeModules(app: App): Promise<void> {
 
   // Wait for all dynamic loading to complete
   await Promise.all(loadPromises);
-}
\ No newline at end of file
+}
diff --git a/core/src/views/PrivateLayout.vue b/core/src/views/PrivateLayout.vue
index 7237b4c..a21c1b3 100644
--- a/core/src/views/PrivateLayout.vue
+++ b/core/src/views/PrivateLayout.vue
@@ -3,12 +3,14 @@ import { RouterView } from 'vue-router';
 import LayoutHeader from '@KTXC/layouts/header/LayoutHeader.vue';
 import { useLayoutStore } from '@KTXC/stores/layoutStore';
 import LayoutSystemMenu from '@KTXC/layouts/menus/LayoutSystemMenu.vue';
+import { useL10nStore } from '@KTXC/stores/l10nStore';
 
 const layoutStore = useLayoutStore();
+const l10nStore = useL10nStore();
 </script>
 
 <template>
-  <v-locale-provider>
+  <v-locale-provider :rtl="l10nStore.isRtl">
     <v-app :class="[layoutStore.miniSidebar ? 'mini-sidebar' : '']">  
       <LayoutHeader />
       <LayoutSystemMenu />
diff --git a/core/src/views/PublicLayout.vue b/core/src/views/PublicLayout.vue
index b174a3e..f61d2e9 100644
--- a/core/src/views/PublicLayout.vue
+++ b/core/src/views/PublicLayout.vue
@@ -2,12 +2,14 @@
 import { RouterView } from 'vue-router';
 import LayoutFooter from '@KTXC/layouts/footer/LayoutFooter.vue';
 import { useLayoutStore } from '@KTXC/stores/layoutStore';
+import { useL10nStore } from '@KTXC/stores/l10nStore';
 
 const layoutStore = useLayoutStore();
+const l10nStore = useL10nStore();
 </script>
 
 <template>
-  <v-locale-provider>
+  <v-locale-provider :rtl="l10nStore.isRtl">
     <v-app :class="[layoutStore.miniSidebar ? 'mini-sidebar' : '']">  
       <v-main class="page-wrapper">
         <v-container fluid>
diff --git a/eslint.config.js b/eslint.config.js
index 7ed7a96..3211190 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -14,5 +14,19 @@ export default [
   },
   pluginJs.configs.recommended,
   ...tseslint.configs.recommended,
-  ...pluginVue.configs['flat/essential']
+  ...pluginVue.configs['flat/essential'],
+  {
+    // The l10n engine is an implementation detail of core/src/plugins/l10n
+    // (the vuetify plugin adapter is the one sanctioned exception). All
+    // other code must use the '@KTXC' useL10n() surface.
+    ignores: ['core/src/plugins/l10n/**', 'core/src/plugins/vuetify/**'],
+    rules: {
+      'no-restricted-imports': ['error', {
+        paths: [{
+          name: 'vue-i18n',
+          message: 'Import useL10n from @KTXC instead; vue-i18n is confined to core/src/plugins/l10n.'
+        }]
+      }]
+    }
+  }
 ];
diff --git a/package-lock.json b/package-lock.json
index 1732a16..0adce51 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -22,6 +22,7 @@
         "vee-validate": "^4.15.1",
         "vite-plugin-vuetify": "^2.1.3",
         "vue": "^3.5.34",
+        "vue-i18n": "^11.4.6",
         "vue-router": "^5.0.7",
         "vue3-perfect-scrollbar": "^2.0.0",
         "vuetify": "^4.0.7"
@@ -640,6 +641,67 @@
         "url": "https://github.com/sponsors/nzakas"
       }
     },
+    "node_modules/@intlify/core-base": {
+      "version": "11.4.6",
+      "resolved": "https://registry.npmjs.org/@intlify/core-base/-/core-base-11.4.6.tgz",
+      "integrity": "sha512-EOeHO95XESK9IFHgHeZXunsM/WBAoCA0DlaWODvx14vKmetAuS97t+l6Xe9hTUqntPpF93vtVSjjUDafw3wXMw==",
+      "license": "MIT",
+      "dependencies": {
+        "@intlify/devtools-types": "11.4.6",
+        "@intlify/message-compiler": "11.4.6",
+        "@intlify/shared": "11.4.6"
+      },
+      "engines": {
+        "node": ">= 22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/kazupon"
+      }
+    },
+    "node_modules/@intlify/devtools-types": {
+      "version": "11.4.6",
+      "resolved": "https://registry.npmjs.org/@intlify/devtools-types/-/devtools-types-11.4.6.tgz",
+      "integrity": "sha512-wowQPpNem56b2d43IJmqbrzG2FeBKe5f/kUGlpNuBmXs6OSqncF8m1+1lxHuW8ISZJF0ma2RkW3iLkw0g0G4VA==",
+      "license": "MIT",
+      "dependencies": {
+        "@intlify/core-base": "11.4.6",
+        "@intlify/shared": "11.4.6"
+      },
+      "engines": {
+        "node": ">= 22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/kazupon"
+      }
+    },
+    "node_modules/@intlify/message-compiler": {
+      "version": "11.4.6",
+      "resolved": "https://registry.npmjs.org/@intlify/message-compiler/-/message-compiler-11.4.6.tgz",
+      "integrity": "sha512-5nj3jULqeTAC1WovwMs1LQWgatTa2pM/rXN9T3XW8rdOtXW9ZF6/GLSNFTKDQmPLwclhPdgUWLJ/4w3fMeeC/Q==",
+      "license": "MIT",
+      "dependencies": {
+        "@intlify/shared": "11.4.6",
+        "source-map-js": "^1.0.2"
+      },
+      "engines": {
+        "node": ">= 22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/kazupon"
+      }
+    },
+    "node_modules/@intlify/shared": {
+      "version": "11.4.6",
+      "resolved": "https://registry.npmjs.org/@intlify/shared/-/shared-11.4.6.tgz",
+      "integrity": "sha512-m1p1HHAMLhqSpTRH7VnXdrN0CQ4y+9vunFkpLkbD8soIuBsnQdawZXqMCgvwI2UVF9Ww7sVaw7g9tV2VO7shoA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/kazupon"
+      }
+    },
     "node_modules/@isaacs/cliui": {
       "version": "8.0.2",
       "resolved": "https://registry.npmjs.org/@isaacs/cliui/-/cliui-8.0.2.tgz",
@@ -6405,6 +6467,33 @@
         "eslint": "^8.57.0 || ^9.0.0 || ^10.0.0"
       }
     },
+    "node_modules/vue-i18n": {
+      "version": "11.4.6",
+      "resolved": "https://registry.npmjs.org/vue-i18n/-/vue-i18n-11.4.6.tgz",
+      "integrity": "sha512-l0gE7Rfy0phCa5ChKYkOq543Wgd39BCK6hkktfr1Ed4D99oRkgPK9ffShASZdeC8OJxGfdWmpYoAaAH6iLEuIg==",
+      "license": "MIT",
+      "dependencies": {
+        "@intlify/core-base": "11.4.6",
+        "@intlify/devtools-types": "11.4.6",
+        "@intlify/shared": "11.4.6",
+        "@vue/devtools-api": "^6.5.0"
+      },
+      "engines": {
+        "node": ">= 22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/kazupon"
+      },
+      "peerDependencies": {
+        "vue": "^3.0.0"
+      }
+    },
+    "node_modules/vue-i18n/node_modules/@vue/devtools-api": {
+      "version": "6.6.4",
+      "resolved": "https://registry.npmjs.org/@vue/devtools-api/-/devtools-api-6.6.4.tgz",
+      "integrity": "sha512-sGhTPMuXqZ1rVOk32RylztWkfXTRhuS7vgAKv0zjqk8gbsHkJ7xfFf+jbySxt7tWObEJwyKaHMikV/WGDiQm8g==",
+      "license": "MIT"
+    },
     "node_modules/vue-router": {
       "version": "5.0.7",
       "resolved": "https://registry.npmjs.org/vue-router/-/vue-router-5.0.7.tgz",
diff --git a/package.json b/package.json
index 31aa9bf..7af2aff 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,8 @@
     "dev:all": "npm run dev && npm run dev:modules",
     "watch": "vite build --mode development --watch",
     "typecheck": "vue-tsc --noEmit",
+    "l10n:extract": "node scripts/l10n-extract.mjs",
+    "l10n:check": "node scripts/l10n-extract.mjs --check",
     "lint": "eslint . --ext .vue,.js,.jsx,.cjs,.mjs,.ts,.tsx,.cts,.mts --fix --ignore-path .gitignore",
     "test": "vitest run --config tests/js/vitest.config.ts",
     "test:unit": "vitest run --config tests/js/vitest.config.ts",
@@ -34,6 +36,7 @@
     "vee-validate": "^4.15.1",
     "vite-plugin-vuetify": "^2.1.3",
     "vue": "^3.5.34",
+    "vue-i18n": "^11.4.6",
     "vue-router": "^5.0.7",
     "vue3-perfect-scrollbar": "^2.0.0",
     "vuetify": "^4.0.7"
diff --git a/scripts/l10n-extract.mjs b/scripts/l10n-extract.mjs
new file mode 100644
index 0000000..e3a6279
--- /dev/null
+++ b/scripts/l10n-extract.mjs
@@ -0,0 +1,184 @@
+#!/usr/bin/env node
+/**
+ * L10N catalog extraction (v1)
+ *
+ * Scans source files for hybrid-style translation calls
+ *
+ *   t('some.key', 'Default English text')
+ *   t('some.key', 'Hello {name}', { name })
+ *
+ * and generates the source-locale catalog (en.json) from the inline
+ * defaults, so the file sent to translators always matches the code.
+ * Keys are authored WITHOUT the namespace prefix; the runtime adds the
+ * namespace (module handle / 'core') when merging catalogs.
+ *
+ * Entries that can only be referenced with dynamic keys can be maintained
+ * by hand in en.manual.json next to the target catalog; they are merged in.
+ *
+ * Usage:
+ *   node scripts/l10n-extract.mjs           # write core/src/l10n/en.json
+ *   node scripts/l10n-extract.mjs --check   # exit 1 if the file is stale
+ */
+
+import { readFileSync, writeFileSync, existsSync, mkdirSync, readdirSync, statSync } from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const rootDir = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
+
+function discoverModuleTargets() {
+  const modulesDir = path.join(rootDir, 'modules');
+  if (!existsSync(modulesDir)) return [];
+  const discovered = [];
+  for (const handle of readdirSync(modulesDir)) {
+    const moduleDir = path.join(modulesDir, handle);
+    const sourceDir = path.join(moduleDir, 'src');
+    if (!existsSync(sourceDir) || !statSync(moduleDir).isDirectory()) continue;
+    const optedIn = existsSync(path.join(moduleDir, 'l10n'))
+      || collectSourceFiles(sourceDir).some((file) => readFileSync(file, 'utf8').includes('useL10n('));
+    if (optedIn) {
+      discovered.push({
+        name: handle,
+        sourceDir,
+        catalogFile: path.join(moduleDir, 'l10n/en.json'),
+      });
+    }
+  }
+  return discovered;
+}
+
+const checkMode = process.argv.includes('--check');
+
+// Matches t('key', 'default'  /  t("key", "default"  — not preceded by a
+// word character or '.', so i18n.global.t(...) and foo.t(...) are ignored.
+const CALL_PATTERN = /(?<![\w$.])t\(\s*(['"])((?:\\.|(?!\1).)+?)\1\s*,\s*(['"])((?:\\.|(?!\3).)*?)\3/g;
+
+const SOURCE_EXTENSIONS = new Set(['.ts', '.vue']);
+const SKIP_DIRS = new Set(['node_modules', 'l10n', 'static', 'dist']);
+
+function collectSourceFiles(dir, files = []) {
+  for (const entry of readdirSync(dir)) {
+    const fullPath = path.join(dir, entry);
+    if (statSync(fullPath).isDirectory()) {
+      if (!SKIP_DIRS.has(entry)) collectSourceFiles(fullPath, files);
+    } else if (SOURCE_EXTENSIONS.has(path.extname(entry))) {
+      files.push(fullPath);
+    }
+  }
+  return files;
+}
+
+function unescape(literal) {
+  return literal.replace(/\\(['"\\])/g, '$1');
+}
+
+function extractTarget(target) {
+  const entries = new Map(); // key -> { default, file }
+  let hasErrors = false;
+
+  for (const file of collectSourceFiles(target.sourceDir)) {
+    const source = readFileSync(file, 'utf8');
+    for (const match of source.matchAll(CALL_PATTERN)) {
+      const key = unescape(match[2]);
+      const defaultText = unescape(match[4]);
+      const relFile = path.relative(rootDir, file);
+
+      if (!/^[\w-]+(\.[\w-]+)*$/.test(key)) {
+        console.error(`✗ ${relFile}: invalid key "${key}" (use dot-separated word segments)`);
+        hasErrors = true;
+        continue;
+      }
+      const existing = entries.get(key);
+      if (existing && existing.default !== defaultText) {
+        console.error(
+          `✗ key "${key}" has conflicting defaults:\n` +
+          `    "${existing.default}" (${existing.file})\n` +
+          `    "${defaultText}" (${relFile})`
+        );
+        hasErrors = true;
+        continue;
+      }
+      entries.set(key, { default: defaultText, file: relFile });
+    }
+  }
+
+  // Nest dotted keys into an object tree
+  const catalog = {};
+  for (const key of [...entries.keys()].sort()) {
+    const segments = key.split('.');
+    let node = catalog;
+    for (const segment of segments.slice(0, -1)) {
+      if (typeof node[segment] === 'string') {
+        console.error(`✗ key "${key}" nests under "${segment}", which is already a message`);
+        hasErrors = true;
+        node = null;
+        break;
+      }
+      node = node[segment] ??= {};
+    }
+    if (node) node[segments.at(-1)] = entries.get(key).default;
+  }
+
+  // Merge hand-maintained entries for dynamic keys
+  const manualFile = path.join(path.dirname(target.catalogFile), 'en.manual.json');
+  if (existsSync(manualFile)) {
+    deepMerge(catalog, JSON.parse(readFileSync(manualFile, 'utf8')));
+  }
+
+  return { catalog, count: entries.size, hasErrors };
+}
+
+function deepMerge(base, extra) {
+  for (const [key, value] of Object.entries(extra)) {
+    if (value && typeof value === 'object' && base[key] && typeof base[key] === 'object') {
+      deepMerge(base[key], value);
+    } else {
+      base[key] = value;
+    }
+  }
+}
+
+function sortDeep(node) {
+  if (typeof node !== 'object' || node === null) return node;
+  return Object.fromEntries(
+    Object.keys(node).sort().map((key) => [key, sortDeep(node[key])])
+  );
+}
+
+// Extraction targets: source tree -> catalog file. Core always; a module is
+// a target once it opts in — has an l10n/ dir or calls useL10n in its src/.
+const targets = [
+  {
+    name: 'core',
+    sourceDir: path.join(rootDir, 'core/src'),
+    catalogFile: path.join(rootDir, 'core/src/l10n/en.json'),
+  },
+  ...discoverModuleTargets(),
+];
+
+let failed = false;
+for (const target of targets) {
+  const { catalog, count, hasErrors } = extractTarget(target);
+  if (hasErrors) {
+    failed = true;
+    continue;
+  }
+  const output = JSON.stringify(sortDeep(catalog), null, 2) + '\n';
+  const relCatalog = path.relative(rootDir, target.catalogFile);
+
+  if (checkMode) {
+    const current = existsSync(target.catalogFile) ? readFileSync(target.catalogFile, 'utf8') : '';
+    if (current !== output) {
+      console.error(`✗ ${relCatalog} is out of sync with source — run: npm run l10n:extract`);
+      failed = true;
+    } else {
+      console.log(`✓ ${relCatalog} in sync (${count} keys)`);
+    }
+  } else {
+    mkdirSync(path.dirname(target.catalogFile), { recursive: true });
+    writeFileSync(target.catalogFile, output);
+    console.log(`✓ wrote ${relCatalog} (${count} keys)`);
+  }
+}
+
+process.exit(failed ? 1 : 0);
diff --git a/vite.config.ts b/vite.config.ts
index e5a8ca6..7f07f5b 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -50,6 +50,11 @@ export default defineConfig(({ mode }) => ({
           dest: '.',
           rename: { stripBase: true },
         },
+        {
+          src: path.resolve(__dirname, 'core/src/l10n/*.json'),
+          dest: 'l10n',
+          rename: { stripBase: true },
+        },
       ],
     }),
   ],