Add persistent language switcher across all learn/parent pages

useNativeLanguage: Now has setNativeLang() that persists to localStorage.
Language selection carries across all pages automatically.

LanguageSwitcher: Compact dropdown component added to learn/layout.tsx
and parent/layout.tsx — visible on every sub-page (top-right).

Parent portal: Language dropdown syncs both UI language and native
language. Parents can switch language mid-session (e.g. when both
parents speak different languages).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

studio-v2/app/learn/layout.tsx

@@ -2,14 +2,16 @@
 
 import { Sidebar } from '@/components/Sidebar'
 import { useTheme } from '@/lib/ThemeContext'
+import { useNativeLanguage } from '@/lib/useNativeLanguage'
+import { LanguageSwitcher } from '@/components/learn/LanguageSwitcher'
 
 /**
  * Shared layout for ALL /learn/* pages.
- * Provides: Sidebar + gradient background + flex container.
- * Individual pages only need to render their content.
+ * Provides: Sidebar + gradient background + language switcher.
  */
 export default function LearnLayout({ children }: { children: React.ReactNode }) {
   const { isDark } = useTheme()
+  const { nativeLang, setNativeLang, isThirdLanguage } = useNativeLanguage()
 
   return (
     <div className={`min-h-screen flex relative overflow-hidden ${
@@ -21,6 +23,14 @@ export default function LearnLayout({ children }: { children: React.ReactNode })
         <Sidebar />
       </div>
       <div className="flex-1 flex flex-col relative z-10 overflow-y-auto scrollbar-hide" style={{ scrollbarWidth: 'none' }}>
+        {/* Sticky language switcher at top-right */}
+        <div className="sticky top-0 z-20 flex justify-end px-4 py-2">
+          <LanguageSwitcher
+            currentLang={nativeLang}
+            onLangChange={setNativeLang}
+            isDark={isDark}
+          />
+        </div>
         {children}
       </div>
     </div>

studio-v2/app/parent/layout.tsx

@@ -2,13 +2,16 @@
 
 import { Sidebar } from '@/components/Sidebar'
 import { useTheme } from '@/lib/ThemeContext'
+import { useNativeLanguage } from '@/lib/useNativeLanguage'
+import { LanguageSwitcher } from '@/components/learn/LanguageSwitcher'
 
 /**
  * Shared layout for ALL /parent/* pages.
- * Same design as learn layout — Sidebar + gradient.
+ * Same design as learn layout — Sidebar + gradient + language switcher.
  */
 export default function ParentLayout({ children }: { children: React.ReactNode }) {
   const { isDark } = useTheme()
+  const { nativeLang, setNativeLang } = useNativeLanguage()
 
   return (
     <div className={`min-h-screen flex relative overflow-hidden ${
@@ -20,6 +23,14 @@ export default function ParentLayout({ children }: { children: React.ReactNode }
         <Sidebar />
       </div>
       <div className="flex-1 flex flex-col relative z-10 overflow-y-auto scrollbar-hide" style={{ scrollbarWidth: 'none' }}>
+        {/* Sticky language switcher at top-right */}
+        <div className="sticky top-0 z-20 flex justify-end px-4 py-2">
+          <LanguageSwitcher
+            currentLang={nativeLang}
+            onLangChange={setNativeLang}
+            isDark={isDark}
+          />
+        </div>
         {children}
       </div>
     </div>

studio-v2/app/parent/page.tsx

@@ -5,6 +5,7 @@ import Link from 'next/link'
 import { useTheme } from '@/lib/ThemeContext'
 import { useLanguage } from '@/lib/LanguageContext'
 import type { Language } from '@/lib/i18n'
+import { useNativeLanguage } from '@/lib/useNativeLanguage'
 
 interface LearningUnit {
   id: string
@@ -28,10 +29,19 @@ const parentT: Record<string, Record<string, string>> = {
 export default function ParentPage() {
   const { isDark } = useTheme()
   const { language, setLanguage } = useLanguage()
+  const { nativeLang, setNativeLang } = useNativeLanguage()
   const [units, setUnits] = useState<LearningUnit[]>([])
   const [isLoading, setIsLoading] = useState(true)
 
-  const t = (key: string) => parentT[key]?.[language] || parentT[key]?.['de'] || key
+  // Use nativeLang for translations (synced with localStorage)
+  const activeLang = nativeLang || language
+  const t = (key: string) => parentT[key]?.[activeLang] || parentT[key]?.['de'] || key
+
+  /** Switch both UI language and native language together */
+  const switchLang = (lang: string) => {
+    setLanguage(lang as Language)
+    setNativeLang(lang)
+  }
 
   const glassCard = isDark
     ? 'bg-white/10 backdrop-blur-xl border border-white/10'
@@ -59,19 +69,9 @@ export default function ParentPage() {
                 {t('greeting')}
               </p>
             </div>
-            <select
-              value={language}
-              onChange={(e) => setLanguage(e.target.value as Language)}
-              className={`text-sm px-2 py-1.5 rounded-lg border-0 ${isDark ? 'bg-white/10 text-white/60' : 'bg-slate-100 text-slate-500'}`}
-            >
-              <option value="de">DE</option>
-              <option value="tr">TR</option>
-              <option value="ar">AR</option>
-              <option value="uk">UK</option>
-              <option value="ru">RU</option>
-              <option value="pl">PL</option>
-              <option value="en">EN</option>
-            </select>
+            <span className={`text-sm ${isDark ? 'text-white/40' : 'text-slate-400'}`}>
+              {activeLang.toUpperCase()}
+            </span>
           </div>
         </div>
       </div>

studio-v2/components/learn/LanguageSwitcher.tsx

@@ -0,0 +1,58 @@
+'use client'
+
+import React from 'react'
+
+interface LanguageSwitcherProps {
+  currentLang: string
+  onLangChange: (lang: string) => void
+  isDark: boolean
+  compact?: boolean
+}
+
+const LANGS = [
+  { code: 'de', label: 'DE' },
+  { code: 'en', label: 'EN' },
+  { code: 'tr', label: 'TR' },
+  { code: 'ar', label: 'AR' },
+  { code: 'uk', label: 'UK' },
+  { code: 'ru', label: 'RU' },
+  { code: 'pl', label: 'PL' },
+]
+
+/**
+ * Compact language switcher for exercise pages.
+ * Shows as dropdown or pill buttons depending on compact prop.
+ */
+export function LanguageSwitcher({ currentLang, onLangChange, isDark, compact = true }: LanguageSwitcherProps) {
+  if (compact) {
+    return (
+      <select
+        value={currentLang}
+        onChange={e => onLangChange(e.target.value)}
+        className={`text-xs px-2 py-1 rounded-lg border-0 cursor-pointer ${
+          isDark ? 'bg-white/10 text-white/70' : 'bg-slate-100 text-slate-600'
+        }`}
+      >
+        {LANGS.map(l => <option key={l.code} value={l.code}>{l.label}</option>)}
+      </select>
+    )
+  }
+
+  return (
+    <div className="flex gap-1">
+      {LANGS.map(l => (
+        <button
+          key={l.code}
+          onClick={() => onLangChange(l.code)}
+          className={`px-2 py-1 rounded-lg text-xs font-medium transition-all ${
+            currentLang === l.code
+              ? 'bg-blue-500 text-white'
+              : isDark ? 'bg-white/5 text-white/40 hover:bg-white/10' : 'bg-slate-100 text-slate-400 hover:bg-slate-200'
+          }`}
+        >
+          {l.label}
+        </button>
+      ))}
+    </div>
+  )
+}

studio-v2/lib/useNativeLanguage.ts

@@ -1,20 +1,26 @@
 'use client'
 
-import { useState, useEffect } from 'react'
+import { useState, useEffect, useCallback } from 'react'
 import { exerciseT, type ExerciseKey } from './exerciseTranslations'
 
 const STORAGE_KEY = 'bp_native_language'
 
 /**
- * Hook to read the user's native language.
- * Returns translation helper for exercise UI texts.
+ * Hook for native language state + translations.
+ * Persists to localStorage. Can be changed at any time (e.g. parent switches language).
  */
 export function useNativeLanguage() {
-  const [nativeLang, setNativeLang] = useState('de')
+  const [nativeLang, setNativeLangState] = useState('de')
 
   useEffect(() => {
     const stored = localStorage.getItem(STORAGE_KEY)
-    if (stored) setNativeLang(stored)
+    if (stored) setNativeLangState(stored)
+  }, [])
+
+  /** Change native language (persists to localStorage) */
+  const setNativeLang = useCallback((lang: string) => {
+    setNativeLangState(lang)
+    localStorage.setItem(STORAGE_KEY, lang)
   }, [])
 
   const isThirdLanguage = nativeLang !== 'de' && nativeLang !== 'en'
@@ -34,5 +40,5 @@ export function useNativeLanguage() {
     return typeof entry === 'string' ? entry : entry.text || ''
   }
 
-  return { nativeLang, isThirdLanguage, t, wordInNative }
+  return { nativeLang, setNativeLang, isThirdLanguage, t, wordInNative }
 }