Merge pull request #1332 from QwenLM/fix-language

Fix multi-language and documentation related issues.

Author: pomelo-nwu

docs/users/features/_meta.ts

@@ -10,4 +10,5 @@ export default {
   mcp: 'MCP',
   'token-caching': 'Token Caching',
   sandbox: 'Sandboxing',
+  language: 'i18n',
 };

docs/users/features/commands.md

@@ -48,7 +48,7 @@ Commands specifically for controlling interface and output language.
 | → `ui [language]`     | Set UI interface language        | `/language ui zh-CN`       |
 | → `output [language]` | Set LLM output language          | `/language output Chinese` |
 
-- Available UI languages: `zh-CN` (Simplified Chinese), `en-US` (English)
+- Available built-in UI languages: `zh-CN` (Simplified Chinese), `en-US` (English), `ru-RU` (Russian), `de-DE` (German)
 - Output language examples: `Chinese`, `English`, `Japanese`, etc.
 
 ### 1.4 Tool and Model Management
@@ -72,17 +72,16 @@ Commands for managing AI tools and models.
 
 Commands for obtaining information and performing system settings.
 
-| Command         | Description                                     | Usage Examples                                   |
-| --------------- | ----------------------------------------------- | ------------------------------------------------ |
-| `/help`         | Display help information for available commands | `/help` or `/?`                                  |
-| `/about`        | Display version information                     | `/about`                                         |
-| `/stats`        | Display detailed statistics for current session | `/stats`                                         |
-| `/settings`     | Open settings editor                            | `/settings`                                      |
-| `/auth`         | Change authentication method                    | `/auth`                                          |
-| `/bug`          | Submit issue about Qwen Code                    | `/bug Button click unresponsive`                 |
-| `/copy`         | Copy last output content to clipboard           | `/copy`                                          |
-| `/quit-confirm` | Show confirmation dialog before quitting        | `/quit-confirm` (shortcut: press `Ctrl+C` twice) |
-| `/quit`         | Exit Qwen Code immediately                      | `/quit` or `/exit`                               |
+| Command     | Description                                     | Usage Examples                   |
+| ----------- | ----------------------------------------------- | -------------------------------- |
+| `/help`     | Display help information for available commands | `/help` or `/?`                  |
+| `/about`    | Display version information                     | `/about`                         |
+| `/stats`    | Display detailed statistics for current session | `/stats`                         |
+| `/settings` | Open settings editor                            | `/settings`                      |
+| `/auth`     | Change authentication method                    | `/auth`                          |
+| `/bug`      | Submit issue about Qwen Code                    | `/bug Button click unresponsive` |
+| `/copy`     | Copy last output content to clipboard           | `/copy`                          |
+| `/quit`     | Exit Qwen Code immediately                      | `/quit` or `/exit`               |
 
 ### 1.6 Common Shortcuts
 

docs/users/features/language.md

@@ -0,0 +1,136 @@
+# Internationalization (i18n) & Language
+
+Qwen Code is built for multilingual workflows: it supports UI localization (i18n/l10n) in the CLI, lets you choose the assistant output language, and allows custom UI language packs.
+
+## Overview
+
+From a user point of view, Qwen Code’s “internationalization” spans multiple layers:
+
+| Capability / Setting     | What it controls                                                       | Where stored                 |
+| ------------------------ | ---------------------------------------------------------------------- | ---------------------------- |
+| `/language ui`           | Terminal UI text (menus, system messages, prompts)                     | `~/.qwen/settings.json`      |
+| `/language output`       | Language the AI responds in (an output preference, not UI translation) | `~/.qwen/output-language.md` |
+| Custom UI language packs | Overrides/extends built-in UI translations                             | `~/.qwen/locales/*.js`       |
+
+## UI Language
+
+This is the CLI’s UI localization layer (i18n/l10n): it controls the language of menus, prompts, and system messages.
+
+### Setting the UI Language
+
+Use the `/language ui` command:
+
+```bash
+/language ui zh-CN    # Chinese
+/language ui en-US    # English
+/language ui ru-RU    # Russian
+/language ui de-DE    # German
+```
+
+Aliases are also supported:
+
+```bash
+/language ui zh       # Chinese
+/language ui en       # English
+/language ui ru       # Russian
+/language ui de       # German
+```
+
+### Auto-detection
+
+On first startup, Qwen Code detects your system locale and sets the UI language automatically.
+
+Detection priority:
+
+1. `QWEN_CODE_LANG` environment variable
+2. `LANG` environment variable
+3. System locale via JavaScript Intl API
+4. Default: English
+
+## LLM Output Language
+
+The LLM output language controls what language the AI assistant responds in, regardless of what language you type your questions in.
+
+### How It Works
+
+The LLM output language is controlled by a rule file at `~/.qwen/output-language.md`. This file is automatically included in the LLM's context during startup, instructing it to respond in the specified language.
+
+### Auto-detection
+
+On first startup, if no `output-language.md` file exists, Qwen Code automatically creates one based on your system locale. For example:
+
+- System locale `zh` creates a rule for Chinese responses
+- System locale `en` creates a rule for English responses
+- System locale `ru` creates a rule for Russian responses
+- System locale `de` creates a rule for German responses
+
+### Manual Setting
+
+Use `/language output <language>` to change:
+
+```bash
+/language output Chinese
+/language output English
+/language output Japanese
+/language output German
+```
+
+Any language name works. The LLM will be instructed to respond in that language.
+
+> [!note]
+>
+> After changing the output language, restart Qwen Code for the change to take effect.
+
+### File Location
+
+```
+~/.qwen/output-language.md
+```
+
+## Configuration
+
+### Via Settings Dialog
+
+1. Run `/settings`
+2. Find "Language" under General
+3. Select your preferred UI language
+
+### Via Environment Variable
+
+```bash
+export QWEN_CODE_LANG=zh
+```
+
+This influences auto-detection on first startup (if you haven’t set a UI language and no `output-language.md` file exists yet).
+
+## Custom Language Packs
+
+For UI translations, you can create custom language packs in `~/.qwen/locales/`:
+
+- Example: `~/.qwen/locales/es.js` for Spanish
+- Example: `~/.qwen/locales/fr.js` for French
+
+User directory takes precedence over built-in translations.
+
+> [!tip]
+>
+> Contributions are welcome! If you’d like to improve built-in translations or add new languages.
+> For a concrete example, see [PR #1238: feat(i18n): add Russian language support](https://github.com/QwenLM/qwen-code/pull/1238).
+
+### Language Pack Format
+
+```javascript
+// ~/.qwen/locales/es.js
+export default {
+  Hello: 'Hola',
+  Settings: 'Configuracion',
+  // ... more translations
+};
+```
+
+## Related Commands
+
+- `/language` - Show current language settings
+- `/language ui [lang]` - Set UI language
+- `/language output <language>` - Set LLM output language
+- `/settings` - Open settings dialog

eslint.config.js

@@ -24,6 +24,8 @@ export default tseslint.config(
       '.integration-tests/**',
       'packages/**/.integration-test/**',
       'dist/**',
+      'docs-site/.next/**',
+      'docs-site/out/**',
     ],
   },
   eslint.configs.recommended,

packages/cli/src/core/initializer.ts

@@ -15,6 +15,7 @@ import { type LoadedSettings, SettingScope } from '../config/settings.js';
 import { performInitialAuth } from './auth.js';
 import { validateTheme } from './theme.js';
 import { initializeI18n } from '../i18n/index.js';
+import { initializeLlmOutputLanguage } from '../ui/commands/languageCommand.js';
 
 export interface InitializationResult {
   authError: string | null;
@@ -41,6 +42,9 @@ export async function initializeApp(
     'auto';
   await initializeI18n(languageSetting);
 
+  // Auto-detect and set LLM output language on first use
+  initializeLlmOutputLanguage();
+
   const authType = settings.merged.security?.auth?.selectedType;
   const authError = await performInitialAuth(config, authType);
 

packages/cli/src/i18n/index.ts

@@ -1,22 +1,28 @@
 /**
  * @license
- * Copyright 2025 Qwen
+ * Copyright 2025 Qwen team
  * SPDX-License-Identifier: Apache-2.0
  */
 
 import * as fs from 'node:fs';
 import * as path from 'node:path';
 import { fileURLToPath, pathToFileURL } from 'node:url';
 import { homedir } from 'node:os';
+import {
+  type SupportedLanguage,
+  getLanguageNameFromLocale,
+} from './languages.js';
 
-export type SupportedLanguage = 'en' | 'zh' | 'ru' | string; // Allow custom language codes
+export type { SupportedLanguage };
+export { getLanguageNameFromLocale };
 
 // State
 let currentLanguage: SupportedLanguage = 'en';
-let translations: Record<string, string> = {};
+let translations: Record<string, string | string[]> = {};
 
 // Cache
-type TranslationDict = Record<string, string>;
+type TranslationValue = string | string[];
+type TranslationDict = Record<string, TranslationValue>;
 const translationCache: Record<string, TranslationDict> = {};
 const loadingPromises: Record<string, Promise<TranslationDict>> = {};
 
@@ -52,11 +58,13 @@ export function detectSystemLanguage(): SupportedLanguage {
   if (envLang?.startsWith('zh')) return 'zh';
   if (envLang?.startsWith('en')) return 'en';
   if (envLang?.startsWith('ru')) return 'ru';
+  if (envLang?.startsWith('de')) return 'de';
 
   try {
     const locale = Intl.DateTimeFormat().resolvedOptions().locale;
     if (locale.startsWith('zh')) return 'zh';
     if (locale.startsWith('ru')) return 'ru';
+    if (locale.startsWith('de')) return 'de';
   } catch {
     // Fallback to default
   }
@@ -224,9 +232,25 @@ export function getCurrentLanguage(): SupportedLanguage {
 
 export function t(key: string, params?: Record<string, string>): string {
   const translation = translations[key] ?? key;
+  if (Array.isArray(translation)) {
+    return key;
+  }
   return interpolate(translation, params);
 }
 
+/**
+ * Get a translation that is an array of strings.
+ * @param key The translation key
+ * @returns The array of strings, or an empty array if not found or not an array
+ */
+export function ta(key: string): string[] {
+  const translation = translations[key];
+  if (Array.isArray(translation)) {
+    return translation;
+  }
+  return [];
+}
+
 export async function initializeI18n(
   lang?: SupportedLanguage | 'auto',
 ): Promise<void> {

packages/cli/src/i18n/languages.ts

@@ -0,0 +1,48 @@
+/**
+ * @license
+ * Copyright 2025 Qwen team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+export type SupportedLanguage = 'en' | 'zh' | 'ru' | 'de' | string;
+
+export interface LanguageDefinition {
+  /** The internal locale code used by the i18n system (e.g., 'en', 'zh'). */
+  code: SupportedLanguage;
+  /** The standard name used in UI settings (e.g., 'en-US', 'zh-CN'). */
+  id: string;
+  /** The full English name of the language (e.g., 'English', 'Chinese'). */
+  fullName: string;
+}
+
+export const SUPPORTED_LANGUAGES: readonly LanguageDefinition[] = [
+  {
+    code: 'en',
+    id: 'en-US',
+    fullName: 'English',
+  },
+  {
+    code: 'zh',
+    id: 'zh-CN',
+    fullName: 'Chinese',
+  },
+  {
+    code: 'ru',
+    id: 'ru-RU',
+    fullName: 'Russian',
+  },
+  {
+    code: 'de',
+    id: 'de-DE',
+    fullName: 'German',
+  },
+];
+
+/**
+ * Maps a locale code to its English language name.
+ * Used for LLM output language instructions.
+ */
+export function getLanguageNameFromLocale(locale: SupportedLanguage): string {
+  const lang = SUPPORTED_LANGUAGES.find((l) => l.code === locale);
+  return lang?.fullName || 'English';
+}