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diff --git a/‎packages/app-shell/src/views/metadata-admin/StudioHomePage.displayLocale-10232.test.tsx‎
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diff --git a/‎packages/app-shell/src/views/metadata-admin/StudioHomePage.tsx‎
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diff --git a/‎packages/app-shell/src/views/metadata-admin/i18n.ts‎
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diff --git a/‎packages/app-shell/src/views/studio-design/DataPillar.savedAtDisplayLocale-10232.test.tsx‎
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diff --git a/‎packages/app-shell/src/views/studio-design/StudioDesignSurface.tsx‎
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diff --git a/‎packages/i18n/src/locales/ar.ts‎
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diff --git a/‎packages/i18n/src/locales/de.ts‎
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@@ -0,0 +1,20 @@
+---
+'@object-ui/app-shell': patch
+'@object-ui/plugin-ai': patch
+'@object-ui/i18n': patch
+---
+
+Two display-locale faces now follow the session's display locale (objectui#10232).
+
+- `@object-ui/plugin-ai` is wired to `@object-ui/i18n` as a whole. The `nl-query`,
+  `ai-form-assist` and `ai-recommendations` components read their strings from a new
+  `ai.*` namespace, translated in all ten locale packs, instead of hard-coded English.
+  The `nl-query` history date, which was formatted in the machine's locale, and the
+  confidence and score percentages now format in the display locale
+  (`useDisplayLocale()`). The package's manifest now names `@object-ui/i18n`, which also
+  puts it inside the repo-wide machine-locale census.
+- `@object-ui/app-shell`: the Studio home page's "recently viewed" times and the Data
+  pillar's last-saved time format in the display locale. They used to be handed
+  `useMetadataLocale()`, which picks the designer's string table and is `en-US` for every
+  language other than zh, so a de-DE session read US English. That hook's doc comment
+  now says it must never be used as an `Intl` locale.
@@ -0,0 +1,104 @@
+/**
+ * ObjectUI
+ * Copyright (c) 2024-present ObjectStack Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * Studio home's "recently viewed" times read the DISPLAY locale, not the
+ * designer's string-table language (objectui#10232).
+ *
+ * The page carries a `locale` of its own — `useMetadataLocale()`, which picks
+ * one of the metadata-admin `t()` tables and is therefore `'en-US'` for every
+ * language that is not zh. `relativeTime` used to be handed that value, so a
+ * de-DE session read "3 days ago". The face now formats with
+ * `useDisplayLocale()`, the channel objectui#9909's surfaces already use.
+ *
+ * Each session is read with the UI language `en` on both sides, so the
+ * string-table language is `'en-US'` in both and only the declared display
+ * locale differs: a reading that still followed `useMetadataLocale()` says the
+ * same thing twice.
+ */
+
+import '@testing-library/jest-dom/vitest';
+import * as React from 'react';
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { render, cleanup, screen } from '@testing-library/react';
+import { MemoryRouter } from 'react-router-dom';
+import { I18nProvider, LocalizationProvider } from '@object-ui/i18n';
+import { isMachineLocale, recordLocaleArgumentsAsync } from '@object-ui/test-support';
+
+const THREE_DAYS = 3 * 24 * 60 * 60 * 1000;
+
+vi.mock('./useMetadata.js', async (importOriginal) => ({
+  ...(await importOriginal<Record<string, unknown>>()),
+  useMetadataClient: () => ({ list: async () => [] }),
+  useMetadataTypes: () => ({ loading: false, entries: [] }),
+  useGlobalDiagnostics: () => ({ summary: { total: 0 }, countsByType: {}, packagesByType: {}, loading: false }),
+}));
+
+vi.mock('./QuickFind.js', () => ({ MetadataQuickFind: () => null }));
+
+vi.mock('../../context/RecentItemsProvider.js', async (importOriginal) => ({
+  ...(await importOriginal<Record<string, unknown>>()),
+  useRecentItems: () => ({
+    recentItems: [
+      {
+        id: 'object:account',
+        label: 'Account',
+        href: '/studio/object/account',
+        type: 'object',
+        visitedAt: new Date(Date.now() - THREE_DAYS).toISOString(),
+      },
+    ],
+    addRecentItem: () => {},
+    clearRecentItems: () => {},
+  }),
+}));
+
+import { StudioHomePage } from './StudioHomePage';
+
+afterEach(cleanup);
+
+/** Mounts the page under a declared display `locale` and returns the recent item's time. */
+async function readVisitTime(locale: string): Promise<string> {
+  render(
+    <I18nProvider config={{ defaultLanguage: 'en', detectBrowserLanguage: false }} persistLanguage={false}>
+      <LocalizationProvider value={{ locale }}>
+        <MemoryRouter>
+          <StudioHomePage />
+        </MemoryRouter>
+      </LocalizationProvider>
+    </I18nProvider>,
+  );
+  const label = await screen.findByText('Account');
+  const text = label.parentElement?.textContent ?? '';
+  cleanup();
+  return text.replace(/\s+/g, ' ');
+}
+
+describe('Studio home — recently viewed times follow the display locale (objectui#10232)', () => {
+  it('says the de-DE face under a de-DE session', async () => {
+    const text = await readVisitTime('de-DE');
+    expect(text, `got: ${text}`).toMatch(/vor 3 Tagen/);
+  });
+
+  it('keeps the en face under an en session', async () => {
+    const text = await readVisitTime('en');
+    expect(text, `got: ${text}`).toMatch(/3 days ago/);
+  });
+
+  it('is a reading of the display locale, not of the string-table language', async () => {
+    expect(await readVisitTime('de-DE')).not.toBe(await readVisitTime('en'));
+  });
+
+  it('every locale-taking call receives the declared tag', async () => {
+    const calls = await recordLocaleArgumentsAsync(async () => {
+      await readVisitTime('de-DE');
+    });
+    expect(calls.some((c) => c.locale === 'de-DE'), `saw: ${JSON.stringify(calls).slice(0, 2000)}`).toBe(true);
+    expect(calls.filter(isMachineLocale), 'these call sites formatted in the machine locale').toEqual([]);
+  });
+});
@@ -44,6 +44,7 @@ import {
   Table2,
 } from 'lucide-react';
 import { Button } from '@object-ui/components';
+import { useDisplayLocale } from '@object-ui/i18n';
 import { useRecentItems, type RecentItem } from '../../context/RecentItemsProvider.js';
 import {
   useMetadataClient,
@@ -118,6 +119,11 @@ function greetingKey(): string {
  * the last hard-coded strings in this file.
  *
  * `numeric: 'auto'` is what turns "1 day ago" into "yesterday" / 「昨天」.
+ *
+ * `locale` is the DISPLAY locale (`useDisplayLocale()`), never the designer's
+ * string-table language from `useMetadataLocale()`: that one collapses every
+ * non-zh language to `'en-US'`, so a de-DE session read "3 days ago" in US
+ * English (objectui#10232).
  */
 function relativeTime(iso: string, locale: string): string {
   const then = new Date(iso).getTime();
@@ -141,6 +147,9 @@ export function StudioHomePage() {
   const { loading, entries } = useMetadataTypes(client);
   const { recentItems } = useRecentItems();
   const locale = useMetadataLocale();
+  // The visit times read the DISPLAY locale — not `locale` above, which picks
+  // this page's strings (objectui#10232).
+  const displayLocale = useDisplayLocale();
   const [searchParams, setSearchParams] = useSearchParams();
 
   const [projectPackages, setProjectPackages] = React.useState<
@@ -421,7 +430,7 @@ export function StudioHomePage() {
                           <span className="min-w-0 flex-1">
                             <span className="block truncate text-sm font-medium">{item.label}</span>
                             <span className="block text-[11px] text-muted-foreground">
-                              {relativeTime(item.visitedAt, locale)}
+                              {relativeTime(item.visitedAt, displayLocale)}
                             </span>
                           </span>
                           <ArrowRight className="h-3.5 w-3.5 text-muted-foreground opacity-0 transition-opacity group-hover:opacity-100" />
 
@@ -4756,6 +4756,14 @@ export function detectLocale(): SupportedLocale {
  * follows the live `useObjectTranslation().language`, so the Studio pillars
  * re-render in lock-step with the console locale — the same source the rest of
  * the app (Home, forms, list views) renders from.
+ *
+ * ⛔ Never hand this value to `Intl` (`Intl.*Format`, `toLocale*String`) as the
+ * locale a date, time or number is formatted in. It picks one of this file's
+ * TWO string tables, so it is `'en-US'` for every language that is not zh — a
+ * de-DE session would read its faces in US English (objectui#10232). Faces
+ * format with `useDisplayLocale()` from `@object-ui/i18n`, the channel every
+ * date and number renderer resolves through; keep this value for `t()` /
+ * `tFormat()` and the other lookups into the tables here.
  */
 export function useMetadataLocale(): SupportedLocale {
   const { language } = useObjectTranslation();
 
@@ -0,0 +1,109 @@
+/**
+ * ObjectUI
+ * Copyright (c) 2024-present ObjectStack Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * The Data pillar's last-saved hint reads the DISPLAY locale, not the
+ * designer's string-table language (objectui#10232).
+ *
+ * The pillar's `locale` is `useMetadataLocale()`, which picks one of the
+ * metadata-admin `t()` tables and is `'en-US'` for every language that is not
+ * zh. The saved time used to be formatted with it, so a de-DE session read
+ * "Saved 03:30 PM". The time is now formatted with `useDisplayLocale()`; the
+ * sentence around it keeps the string-table language.
+ *
+ * The UI language is `en` in both sessions, so only the declared display
+ * locale differs. The saved time is "now", so the faces are told apart by the
+ * convention, not by a fixed clock: a 24-hour de-DE time carries no day
+ * period, an en one does.
+ */
+
+import '@testing-library/jest-dom/vitest';
+import * as React from 'react';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { render, screen, fireEvent, cleanup } from '@testing-library/react';
+import { MemoryRouter } from 'react-router-dom';
+import { I18nProvider, LocalizationProvider } from '@object-ui/i18n';
+import { isMachineLocale, recordLocaleArgumentsAsync } from '@object-ui/test-support';
+
+const objectDef = {
+  name: 'showcase_task',
+  label: 'Task',
+  fields: [{ name: 'title', label: 'Title', type: 'text' }],
+};
+
+const mockClient = {
+  list: vi.fn(async () => [{ name: 'showcase_task', label: 'Task' }]),
+  listDrafts: vi.fn(async () => []),
+  layered: vi.fn(async () => ({ effective: objectDef, code: objectDef })),
+  getDraft: vi.fn(async () => null),
+  save: vi.fn(async () => ({})),
+};
+
+vi.mock('../metadata-admin/useMetadata', async (importOriginal) => {
+  const mod = await importOriginal<typeof import('../metadata-admin/useMetadata')>();
+  return {
+    ...mod,
+    useMetadataClient: () => mockClient,
+    useMetadataTypes: () => ({ entries: [] }),
+  };
+});
+
+vi.mock('./packages-io', async (importOriginal) => {
+  const mod = await importOriginal<typeof import('./packages-io')>();
+  return { ...mod, fetchPackages: vi.fn(async () => []) };
+});
+
+vi.mock('@object-ui/react', async (importOriginal) => {
+  const mod = await importOriginal<typeof import('@object-ui/react')>();
+  return { ...mod, useAdapter: () => ({}) };
+});
+
+import { DataPillar } from './StudioDesignSurface';
+
+afterEach(cleanup);
+
+/** Mounts the pillar under a declared display `locale`, makes an edit, and returns the saved hint once the auto-save lands. */
+async function readSavedHint(locale: string): Promise<string> {
+  render(
+    <I18nProvider config={{ defaultLanguage: 'en', detectBrowserLanguage: false }} persistLanguage={false}>
+      <LocalizationProvider value={{ locale }}>
+        <MemoryRouter initialEntries={['/studio/com.example.showcase/data']}>
+          <DataPillar packageId="com.example.showcase" />
+        </MemoryRouter>
+      </LocalizationProvider>
+    </I18nProvider>,
+  );
+  fireEvent.click(await screen.findByRole('button', { name: 'Form' }));
+  // An edit sets `dirty`; the debounced auto-save lands it and shows the hint.
+  fireEvent.click((await screen.findAllByRole('button', { name: /Add field/i }))[0]);
+  const hint = await screen.findByTestId('data-saved-at', undefined, { timeout: 5000 });
+  const text = hint.textContent ?? '';
+  cleanup();
+  return text;
+}
+
+describe('Data pillar — the last-saved time follows the display locale (objectui#10232)', () => {
+  it('says the de-DE face under a de-DE session', async () => {
+    const text = await readSavedHint('de-DE');
+    expect(text, `got: ${text}`).toMatch(/\b\d{2}:\d{2}\b/);
+    expect(text, `got: ${text}`).not.toMatch(/\b(AM|PM)\b/);
+  });
+
+  it('keeps the en face under an en session', async () => {
+    const text = await readSavedHint('en');
+    expect(text, `got: ${text}`).toMatch(/\d{2}:\d{2}\s(AM|PM)/);
+  });
+
+  it('every locale-taking call receives the declared tag', async () => {
+    const calls = await recordLocaleArgumentsAsync(async () => {
+      await readSavedHint('de-DE');
+    });
+    expect(calls.some((c) => c.locale === 'de-DE'), `saw: ${JSON.stringify(calls).slice(0, 2000)}`).toBe(true);
+    expect(calls.filter(isMachineLocale), 'these call sites formatted in the machine locale').toEqual([]);
+  });
+});
@@ -116,6 +116,7 @@ import { SurfaceDeepLinkProvider, useRequestedSurface } from './surfaceDeepLinkC
 import { buildObjectSkeleton, buildFlowSkeleton, buildAppSkeleton, buildPermissionSkeleton } from './skeletons.js';
 import { OWD_CREATE_MODELS, OWD_DEFAULT, type OwdCreateModel } from './owd-sharing.js';
 import { t, tFormat, translateMetadataType, useMetadataLocale } from '../metadata-admin/i18n.js';
+import { useDisplayLocale } from '@object-ui/i18n';
 import { SuggestedBindingsPanel } from '../../components/SuggestedBindingsPanel.js';
 import { AppNavCanvas } from '../metadata-admin/previews/AppNavCanvas.js';
 import {
@@ -2656,6 +2657,10 @@ export function DataPillar({
   const client = useMetadataClient();
   const adapter = useAdapter();
   const locale = useMetadataLocale();
+  // The last-saved time reads the DISPLAY locale — not `locale` above, which
+  // picks the pillar's strings and is `'en-US'` for every non-zh language
+  // (objectui#10232).
+  const displayLocale = useDisplayLocale();
   // Live server JSONSchemas per metadata type (`/meta/types`) — handed to the
   // Actions/Hooks config panels so their forms are driven by the real metadata
   // contract (and stay forward-compatible when the server spec adds fields).
@@ -3173,7 +3178,7 @@ export function DataPillar({
         ) : savedAt && !dirty ? (
           <span className="ml-auto text-[11px] text-muted-foreground" data-testid="data-saved-at">
             {tFormat('engine.studio.data.lastSaved', locale, {
-              time: savedAt.toLocaleTimeString(locale, { hour: '2-digit', minute: '2-digit' }),
+              time: savedAt.toLocaleTimeString(displayLocale, { hour: '2-digit', minute: '2-digit' }),
             })}
           </span>
         ) : null}
 
@@ -2927,6 +2927,31 @@ const ar = {
     openProduction: "فتح بيئة الإنتاج",
     manageEnvironments: "إدارة البيئات",
   },
+  ai: {
+    nlQuery: {
+      placeholder: "اطرح سؤالًا حول بياناتك…",
+      ask: "اسأل",
+      results: "النتائج",
+      match: "نسبة التطابق: {{percent}}",
+      simulatedSummary: "نتائج: {{query}}",
+      noResults: "لم يتم العثور على سجلات مطابقة",
+      recentQueries: "الاستعلامات الأخيرة",
+    },
+    formAssist: {
+      title: "اقتراحات الذكاء الاصطناعي",
+      suggestionCount: "عدد الاقتراحات: {{count}}",
+      suggestionCountOne: "عدد الاقتراحات: {{count}}",
+      applyAll: "تطبيق الكل",
+      confidence: "الثقة: {{percent}}",
+      appliedCount: "عدد الاقتراحات المطبّقة: {{count}}",
+      appliedCountOne: "عدد الاقتراحات المطبّقة: {{count}}",
+    },
+    recommendations: {
+      title: "التوصيات",
+      generating: "جارٍ إنشاء التوصيات…",
+      empty: "لا توجد توصيات متاحة",
+    },
+  },
   aiApprovals: {
     title: "موافقات الذكاء الاصطناعي",
     description: "إجراءات اقترحها وكيل ذكاء اصطناعي وتحتاج إلى مراجعة بشرية قبل تنفيذها.",
 
@@ -2915,6 +2915,31 @@ const de = {
     openProduction: "Produktion öffnen",
     manageEnvironments: "Umgebungen verwalten",
   },
+  ai: {
+    nlQuery: {
+      placeholder: "Stellen Sie eine Frage zu Ihren Daten…",
+      ask: "Fragen",
+      results: "Ergebnisse",
+      match: "{{percent}} Übereinstimmung",
+      simulatedSummary: "Ergebnisse für: {{query}}",
+      noResults: "Keine passenden Datensätze gefunden",
+      recentQueries: "Letzte Abfragen",
+    },
+    formAssist: {
+      title: "KI-Vorschläge",
+      suggestionCount: "{{count}} Vorschläge",
+      suggestionCountOne: "{{count}} Vorschlag",
+      applyAll: "Alle übernehmen",
+      confidence: "{{percent}} Konfidenz",
+      appliedCount: "{{count}} Vorschläge übernommen",
+      appliedCountOne: "{{count}} Vorschlag übernommen",
+    },
+    recommendations: {
+      title: "Empfehlungen",
+      generating: "Empfehlungen werden generiert…",
+      empty: "Keine Empfehlungen verfügbar",
+    },
+  },
   aiApprovals: {
     title: "KI-Genehmigungen",
     description: "Von einem KI-Agenten vorgeschlagene Aktionen, die vor der Ausführung eine menschliche Prüfung benötigen.",