diff --git a/packages/commands/src/commands/config/set.ts b/packages/commands/src/commands/config/set.ts
index ea75a4a..67c718a 100644
--- a/packages/commands/src/commands/config/set.ts
+++ b/packages/commands/src/commands/config/set.ts
@@ -11,7 +11,7 @@ export default defineCommand({
       type: "string",
       valueHint: "<key>",
       description:
-        "Config key (base_url, output, output_dir, timeout, api_key, access_token, access_key_id, access_key_secret, security_token, default_*_model, workspace_id)",
+        "Config key (language, base_url, output, output_dir, timeout, api_key, access_token, access_key_id, access_key_secret, security_token, default_*_model, workspace_id)",
       required: true,
     },
     value: {
@@ -22,6 +22,7 @@ export default defineCommand({
     },
   },
   exampleArgs: [
+    "--key language --value zh-CN",
     "--key output --value json",
     "--key timeout --value 600",
     "--key base_url --value https://dashscope.aliyuncs.com",
diff --git a/packages/commands/src/commands/config/shared.ts b/packages/commands/src/commands/config/shared.ts
index 2473f80..8cd5446 100644
--- a/packages/commands/src/commands/config/shared.ts
+++ b/packages/commands/src/commands/config/shared.ts
@@ -1,7 +1,13 @@
-import { BailianError, ExitCode, normalizeModelBaseUrl } from "bailian-cli-core";
+import {
+  BailianError,
+  ExitCode,
+  normalizeModelBaseUrl,
+  SUPPORTED_LANGUAGES,
+} from "bailian-cli-core";
 
 /** Config keys that `config set` / `config ui` accept for read/write. */
 export const VALID_KEYS = [
+  "language",
   "base_url",
   "output",
   "output_dir",
@@ -47,6 +53,7 @@ export const UI_VALID_KEYS = [...VALID_KEYS, ...UI_EXTRA_KEYS] as const;
 
 // Keys the UI renders as a fixed-choice dropdown instead of a free-text input.
 export const UI_ENUM_KEYS: Record<string, string[]> = {
+  language: [...SUPPORTED_LANGUAGES],
   output: ["text", "json"],
   console_site: ["domestic", "international"],
 };
@@ -144,6 +151,13 @@ export function validateAndCoerce(key: string, value: string): string | number {
     );
   }
 
+  if (resolvedKey === "language" && !(SUPPORTED_LANGUAGES as readonly string[]).includes(value)) {
+    throw new BailianError(
+      `Invalid language "${value}". Valid values: ${SUPPORTED_LANGUAGES.join(", ")}`,
+      ExitCode.USAGE,
+    );
+  }
+
   if (resolvedKey === "output" && !["text", "json"].includes(value)) {
     throw new BailianError(
       `Invalid output format "${value}". Valid values: text, json`,
diff --git a/packages/commands/src/commands/config/show.ts b/packages/commands/src/commands/config/show.ts
index ee6e3fa..ca35803 100644
--- a/packages/commands/src/commands/config/show.ts
+++ b/packages/commands/src/commands/config/show.ts
@@ -1,4 +1,4 @@
-import { defineCommand, detectOutputFormat, maskToken } from "bailian-cli-core";
+import { DEFAULT_LANGUAGE, defineCommand, detectOutputFormat, maskToken } from "bailian-cli-core";
 import { emitResult } from "bailian-cli-runtime";
 import { SECRET_KEYS } from "./shared.ts";
 
@@ -14,6 +14,7 @@ export default defineCommand({
 
     const result: Record<string, unknown> = {
       ...file,
+      language: file.language ?? DEFAULT_LANGUAGE,
       base_url: client.baseUrl,
       output: settings.output,
       timeout: settings.timeout,
diff --git a/packages/commands/tests/e2e/config.e2e.test.ts b/packages/commands/tests/e2e/config.e2e.test.ts
index e9b1bdb..877170f 100644
--- a/packages/commands/tests/e2e/config.e2e.test.ts
+++ b/packages/commands/tests/e2e/config.e2e.test.ts
@@ -189,6 +189,19 @@ describe("e2e: config", () => {
     }
   });
 
+  test("config set language 拒绝不支持的值", async () => {
+    const { stderr, exitCode } = await runCommandE2e(CONFIG_ROUTES, [
+      "config",
+      "set",
+      "--key",
+      "language",
+      "--value",
+      "fr-FR",
+    ]);
+    expect(exitCode).toBe(2);
+    expect(stderr).toMatch(/Invalid language|en-US, zh-CN/i);
+  });
+
   test("config set 非法 key 时退出为用法错误", async () => {
     const { stderr, exitCode } = await runCommandE2e(CONFIG_ROUTES, [
       "config",
diff --git a/packages/core/src/config/index.ts b/packages/core/src/config/index.ts
index 48c89a5..029905b 100644
--- a/packages/core/src/config/index.ts
+++ b/packages/core/src/config/index.ts
@@ -1,5 +1,13 @@
-export type { ConfigFile, Region, Identity, Settings } from "./schema.ts";
-export { BAILIAN_HOST, CONFIG_FILE_KEYS, DOCS_HOSTS, REGIONS, parseConfigFile } from "./schema.ts";
+export type { ConfigFile, Language, Region, Identity, Settings } from "./schema.ts";
+export {
+  BAILIAN_HOST,
+  CONFIG_FILE_KEYS,
+  DEFAULT_LANGUAGE,
+  DOCS_HOSTS,
+  REGIONS,
+  SUPPORTED_LANGUAGES,
+  parseConfigFile,
+} from "./schema.ts";
 export { normalizeConfigName, readConfigFile, writeConfigFile } from "./loader.ts";
 export {
   activateConfigProfile,
diff --git a/packages/core/src/config/schema.ts b/packages/core/src/config/schema.ts
index 56f4ff1..2196bb7 100644
--- a/packages/core/src/config/schema.ts
+++ b/packages/core/src/config/schema.ts
@@ -16,7 +16,12 @@ export const BAILIAN_HOST = "https://bailian.cn-beijing.aliyuncs.com";
 
 export type Region = keyof typeof REGIONS;
 
+export const SUPPORTED_LANGUAGES = ["en-US", "zh-CN"] as const;
+export type Language = (typeof SUPPORTED_LANGUAGES)[number];
+export const DEFAULT_LANGUAGE: Language = "en-US";
+
 export interface ConfigFile {
+  language?: Language;
   api_key?: string;
   /** OAuth-style token from `bl auth login --console` callback; sent as `Authorization: Bearer …` */
   access_token?: string;
@@ -45,6 +50,7 @@ export interface ConfigFile {
 }
 
 export const CONFIG_FILE_KEYS = [
+  "language",
   "api_key",
   "access_token",
   "access_key_id",
@@ -90,6 +96,11 @@ export function parseConfigFile(raw: unknown): ConfigFile {
   const obj = raw as Record<string, unknown>;
   const out: ConfigFile = {};
 
+  if (
+    typeof obj.language === "string" &&
+    (SUPPORTED_LANGUAGES as readonly string[]).includes(obj.language)
+  )
+    out.language = obj.language as Language;
   if (typeof obj.api_key === "string") out.api_key = obj.api_key;
   if (typeof obj.access_token === "string" && obj.access_token.length > 0)
     out.access_token = obj.access_token;
diff --git a/packages/core/src/types/command.ts b/packages/core/src/types/command.ts
index 4bd14be..fb31428 100644
--- a/packages/core/src/types/command.ts
+++ b/packages/core/src/types/command.ts
@@ -4,6 +4,8 @@ import type { AuthStore } from "../auth/store.ts";
 import type { Client } from "../client/client.ts";
 import type { CommandPackManager } from "./command-pack-manager.ts";
 
+export type LocalizedText = string | { readonly "en-US": string; readonly "zh-CN": string };
+
 // ── Flag definitions ─────────────────────────────────────────────────────────
 // Flags are keyed by camelCase name (the key IS the parsed flag name, e.g.
 // `maxTokens` ↔ `--max-tokens`). The flag's type drives both runtime parsing
@@ -12,12 +14,12 @@ import type { CommandPackManager } from "./command-pack-manager.ts";
 /** A presence flag: `--quiet`. No value; absent → false. */
 export interface SwitchFlag {
   type: "switch";
-  description: string;
+  description: LocalizedText;
 }
 /** A value flag: `--prompt <text>`, `--n <count>`, `--watermark true|false`. */
 export interface ValueFlag {
   type: "string" | "number" | "boolean" | "array";
-  description: string;
+  description: LocalizedText;
   valueHint: string;
   required?: boolean;
   /**
@@ -70,26 +72,44 @@ export const GLOBAL_FLAGS = {
   output: {
     type: "string",
     valueHint: "<format>",
-    description: "Output format: text, json",
+    description: { "en-US": "Output format: text, json", "zh-CN": "输出格式：text、json" },
   },
   timeout: {
     type: "number",
     valueHint: "<seconds>",
-    description: "Request timeout",
+    description: { "en-US": "Request timeout", "zh-CN": "请求超时时间" },
+  },
+  quiet: {
+    type: "switch",
+    description: { "en-US": "Suppress non-essential output", "zh-CN": "隐藏非必要输出" },
   },
-  quiet: { type: "switch", description: "Suppress non-essential output" },
   verbose: {
     type: "switch",
-    description: "Print HTTP request/response details",
+    description: {
+      "en-US": "Print HTTP request/response details",
+      "zh-CN": "打印 HTTP 请求和响应详情",
+    },
+  },
+  dryRun: {
+    type: "switch",
+    description: { "en-US": "Dry run mode", "zh-CN": "仅预览，不实际执行" },
   },
-  dryRun: { type: "switch", description: "Dry run mode" },
   config: {
     type: "string",
     valueHint: "<name>",
-    description: "Use a config profile for this command",
+    description: {
+      "en-US": "Use a config profile for this command",
+      "zh-CN": "为当前命令使用指定配置 Profile",
+    },
+  },
+  help: {
+    type: "switch",
+    description: { "en-US": "Show help", "zh-CN": "显示帮助信息" },
+  },
+  version: {
+    type: "switch",
+    description: { "en-US": "Print version", "zh-CN": "显示版本信息" },
   },
-  help: { type: "switch", description: "Show help" },
-  version: { type: "switch", description: "Print version" },
 } satisfies FlagsDef;
 
 /** Command-scoped flag for commands that support parallel API calls. */
@@ -111,8 +131,16 @@ export const ASYNC_FLAG = {
 
 /** Model 域凭证/连接 flag,`auth: "apiKey"` 命令可见。 */
 export const MODEL_AUTH_FLAGS = {
-  apiKey: { type: "string", valueHint: "<key>", description: "API key" },
-  baseUrl: { type: "string", valueHint: "<url>", description: "API base URL" },
+  apiKey: {
+    type: "string",
+    valueHint: "<key>",
+    description: { "en-US": "API key", "zh-CN": "API Key" },
+  },
+  baseUrl: {
+    type: "string",
+    valueHint: "<url>",
+    description: { "en-US": "API base URL", "zh-CN": "API Base URL" },
+  },
 } satisfies FlagsDef;
 
 /** Console 域目标/作用域 flag,`auth: "console"` 命令可见。 */
@@ -120,22 +148,34 @@ export const CONSOLE_AUTH_FLAGS = {
   consoleRegion: {
     type: "string",
     valueHint: "<region>",
-    description: "Console gateway region (e.g. cn-beijing, ap-southeast-1)",
+    description: {
+      "en-US": "Console gateway region (e.g. cn-beijing, ap-southeast-1)",
+      "zh-CN": "控制台网关地域（例如 cn-beijing、ap-southeast-1）",
+    },
   },
   consoleSite: {
     type: "string",
     valueHint: "<site>",
-    description: "Console site: domestic, international",
+    description: {
+      "en-US": "Console site: domestic, international",
+      "zh-CN": "控制台站点：domestic、international",
+    },
   },
   consoleSwitchAgent: {
     type: "number",
     valueHint: "<uid>",
-    description: "Switch agent UID for delegated access",
+    description: {
+      "en-US": "Switch agent UID for delegated access",
+      "zh-CN": "切换代理访问的 UID",
+    },
   },
   workspaceId: {
     type: "string",
     valueHint: "<id>",
-    description: "Workspace ID (env: BAILIAN_WORKSPACE_ID)",
+    description: {
+      "en-US": "Workspace ID (env: BAILIAN_WORKSPACE_ID)",
+      "zh-CN": "Workspace ID（环境变量：BAILIAN_WORKSPACE_ID）",
+    },
   },
 } satisfies FlagsDef;
 
@@ -144,17 +184,26 @@ export const OPENAPI_AUTH_FLAGS = {
   accessKeyId: {
     type: "string",
     valueHint: "<key>",
-    description: "Alibaba Cloud Access Key ID (env: ALIBABA_CLOUD_ACCESS_KEY_ID)",
+    description: {
+      "en-US": "Alibaba Cloud Access Key ID (env: ALIBABA_CLOUD_ACCESS_KEY_ID)",
+      "zh-CN": "阿里云 Access Key ID（环境变量：ALIBABA_CLOUD_ACCESS_KEY_ID）",
+    },
   },
   accessKeySecret: {
     type: "string",
     valueHint: "<key>",
-    description: "Alibaba Cloud Access Key Secret (env: ALIBABA_CLOUD_ACCESS_KEY_SECRET)",
+    description: {
+      "en-US": "Alibaba Cloud Access Key Secret (env: ALIBABA_CLOUD_ACCESS_KEY_SECRET)",
+      "zh-CN": "阿里云 Access Key Secret（环境变量：ALIBABA_CLOUD_ACCESS_KEY_SECRET）",
+    },
   },
   securityToken: {
     type: "string",
     valueHint: "<token>",
-    description: "Alibaba Cloud STS Security Token (env: ALIBABA_CLOUD_SECURITY_TOKEN)",
+    description: {
+      "en-US": "Alibaba Cloud STS Security Token (env: ALIBABA_CLOUD_SECURITY_TOKEN)",
+      "zh-CN": "阿里云 STS Security Token（环境变量：ALIBABA_CLOUD_SECURITY_TOKEN）",
+    },
   },
 } satisfies FlagsDef;
 
@@ -204,7 +253,7 @@ export interface CommandContext<F extends FlagsDef = FlagsDef> {
  * {@link AnyCommand}; the precise typing lives at the `defineCommand` call site.
  */
 export interface Command<F extends FlagsDef = FlagsDef> {
-  description: string;
+  description: LocalizedText;
   /** Credential this command requires. See {@link AuthRequirement}. */
   auth: AuthRequirement;
   /** Usage line arg portion, e.g. "--prompt <text> [flags]". Manually written. */
diff --git a/packages/core/src/types/index.ts b/packages/core/src/types/index.ts
index bafd242..b1f5a4e 100644
--- a/packages/core/src/types/index.ts
+++ b/packages/core/src/types/index.ts
@@ -2,6 +2,7 @@ export type {
   Command,
   AnyCommand,
   CommandContext,
+  LocalizedText,
   FlagDef,
   FlagsDef,
   ParsedFlags,
diff --git a/packages/core/tests/index.test.ts b/packages/core/tests/index.test.ts
index b8aaf7f..44eb765 100644
--- a/packages/core/tests/index.test.ts
+++ b/packages/core/tests/index.test.ts
@@ -311,6 +311,11 @@ test("parseConfigFile ignores obsolete region field", () => {
   expect("region" in f).toBe(false);
 });
 
+test("parseConfigFile accepts only supported languages", () => {
+  expect(parseConfigFile({ language: "zh-CN" }).language).toBe("zh-CN");
+  expect(parseConfigFile({ language: "fr-FR" }).language).toBeUndefined();
+});
+
 test("parseConfigFile accepts only well-formed http(s) base_url", () => {
   expect(parseConfigFile({ base_url: "https://dashscope.aliyuncs.com" }).base_url).toBe(
     "https://dashscope.aliyuncs.com",
diff --git a/packages/runtime/package.json b/packages/runtime/package.json
index 79cc59d..abceb73 100644
--- a/packages/runtime/package.json
+++ b/packages/runtime/package.json
@@ -43,6 +43,7 @@
     "bailian-cli-core": "workspace:*",
     "boxen": "catalog:",
     "chalk": "catalog:",
+    "i18next": "catalog:",
     "undici": "catalog:"
   },
   "devDependencies": {
diff --git a/packages/runtime/src/create-cli.ts b/packages/runtime/src/create-cli.ts
index 6eb03a1..38da2e1 100644
--- a/packages/runtime/src/create-cli.ts
+++ b/packages/runtime/src/create-cli.ts
@@ -12,6 +12,7 @@ import {
 import type { AnyCommand, FlagsDef, Identity, ParsedFlags, SourceFlags } from "bailian-cli-core";
 import {
   CONSOLE_AUTH_FLAGS,
+  DEFAULT_LANGUAGE,
   GLOBAL_FLAGS,
   MODEL_AUTH_FLAGS,
   OPENAPI_AUTH_FLAGS,
@@ -28,10 +29,11 @@ import {
 } from "bailian-cli-core";
 import { setupProxyFromEnv } from "./proxy.ts";
 import { handleError } from "./error-handler.ts";
-import { printWelcomeBanner, printQuickStart } from "./output/banner.ts";
+import { printQuickStart } from "./output/banner.ts";
 import { loadCommandPacks } from "./command-packs/load.ts";
 import { createCommandPackManager } from "./command-packs/manager.ts";
 import type { CommandPackPolicy } from "./command-packs/types.ts";
+import { createTranslator } from "./i18n.ts";
 
 /** Per-product identity injected by each CLI entrypoint (bl / rag / …). */
 export interface CliOptions {
@@ -60,6 +62,20 @@ function pick(obj: Record<string, unknown>, keys: string[]): Record<string, unkn
   return out;
 }
 
+/** Read only the existing `--config` flag so locale follows the selected Profile before dispatch. */
+function pickConfigFlag(argv: string[]): Partial<SourceFlags> {
+  for (let argumentIndex = 0; argumentIndex < argv.length; argumentIndex++) {
+    const argument = argv[argumentIndex];
+    if (argument === "--config") {
+      return { config: argv[argumentIndex + 1] };
+    }
+    if (argument?.startsWith("--config=")) {
+      return { config: argument.slice("--config=".length) };
+    }
+  }
+  return {};
+}
+
 /**
  * 进程级一次性设置：代理初始化、Ctrl+C、stdout EPIPE。
  * 属进程生命周期行为，装一次即可，不进 per-command 中间件。
@@ -94,19 +110,26 @@ export function createCli(commands: Record<string, AnyCommand>, opts: CliOptions
   const identity: Identity = { binName, version, npmPackage, clientName };
   const commandPackPolicy = opts.commandPacks ?? { supported: {} };
   const commandPackManager = createCommandPackManager(identity, commandPackPolicy);
-  let registryPromise: Promise<CommandRegistry> | undefined;
+  let loadedCommandPacksPromise: ReturnType<typeof loadCommandPacks> | undefined;
 
   installProcessHandlers(binName);
 
   const runMiddleware = compose([versionCheckStage, telemetryStage, authStage, runCommandStage]);
 
-  function getRegistry(): Promise<CommandRegistry> {
-    if (!registryPromise) {
-      registryPromise = loadCommandPacks(commands, identity, commandPackPolicy).then(
-        (loaded) => new CommandRegistry(loaded.commands, binName),
-      );
+  function getLoadedCommandPacks(): ReturnType<typeof loadCommandPacks> {
+    if (!loadedCommandPacksPromise) {
+      loadedCommandPacksPromise = loadCommandPacks(commands, identity, commandPackPolicy);
     }
-    return registryPromise;
+    return loadedCommandPacksPromise;
+  }
+
+  async function getRegistry(argv: string[]): Promise<CommandRegistry> {
+    const localeSources = buildSources(pickConfigFlag(argv));
+    const [translator, loaded] = await Promise.all([
+      createTranslator(localeSources.file.language ?? DEFAULT_LANGUAGE),
+      getLoadedCommandPacks(),
+    ]);
+    return new CommandRegistry(loaded.commands, binName, translator);
   }
 
   /** Render help for `path`; root ([]) doubles as the onboarding / login guide. */
@@ -133,7 +156,7 @@ export function createCli(commands: Record<string, AnyCommand>, opts: CliOptions
     if (hasKey) {
       if (opts.quickStartTasks?.length) printQuickStart(opts.quickStartTasks);
     } else {
-      printWelcomeBanner(binName);
+      registry.printWelcome();
     }
   }
 
@@ -207,7 +230,8 @@ export function createCli(commands: Record<string, AnyCommand>, opts: CliOptions
 
   return {
     run(argv: string[] = process.argv.slice(2)) {
-      return getRegistry()
+      return Promise.resolve()
+        .then(() => getRegistry(argv))
         .then((registry) => dispatch(registry, argv))
         .catch(
           (err) => flushTelemetry(1000).finally(() => handleError(err, binName)) as unknown as void,
diff --git a/packages/runtime/src/i18n.ts b/packages/runtime/src/i18n.ts
new file mode 100644
index 0000000..8326333
--- /dev/null
+++ b/packages/runtime/src/i18n.ts
@@ -0,0 +1,56 @@
+import { createInstance, type ResourceLanguage, type TOptions } from "i18next";
+import {
+  DEFAULT_LANGUAGE,
+  SUPPORTED_LANGUAGES,
+  type Language,
+  type LocalizedText,
+} from "bailian-cli-core";
+
+export type Translate = (key: string, options?: Record<string, unknown>) => string;
+
+/** A colocated namespace that a product or feature can register with the CLI runtime. */
+export interface CliMessageBundle {
+  namespace: string;
+  resources: Partial<Record<Language, ResourceLanguage>>;
+}
+
+/** Per-CLI translation surface. The mutable i18next instance stays private to runtime. */
+export interface Translator {
+  language: Language;
+  translate: Translate;
+  localize(text: LocalizedText): string;
+}
+
+export async function createTranslator(
+  language: Language,
+  bundles: readonly CliMessageBundle[] = [],
+): Promise<Translator> {
+  const instance = createInstance();
+
+  await instance.init({
+    lng: language,
+    fallbackLng: DEFAULT_LANGUAGE,
+    supportedLngs: [...SUPPORTED_LANGUAGES],
+    initAsync: false,
+    interpolation: { escapeValue: false },
+  });
+
+  for (const bundle of bundles) {
+    for (const supportedLanguage of SUPPORTED_LANGUAGES) {
+      const resource = bundle.resources[supportedLanguage];
+      if (resource) {
+        instance.addResourceBundle(supportedLanguage, bundle.namespace, resource, true, false);
+      }
+    }
+  }
+
+  return {
+    language,
+    localize(text) {
+      return typeof text === "string" ? text : text[language];
+    },
+    translate(key, options = {}) {
+      return String(instance.t(key, options as TOptions));
+    },
+  };
+}
diff --git a/packages/runtime/src/output/banner.ts b/packages/runtime/src/output/banner.ts
index cb88e0c..d3c3e6e 100644
--- a/packages/runtime/src/output/banner.ts
+++ b/packages/runtime/src/output/banner.ts
@@ -1,16 +1,38 @@
 import { API_KEY_PAGE, TOKEN_PLAN_PAGE } from "../urls.ts";
+import type { LocalizedText } from "bailian-cli-core";
+import type { Translator } from "../i18n.ts";
 import { ansi } from "./color.ts";
 
-export function printWelcomeBanner(cliName: string): void {
+const WELCOME_TEXT = {
+  title: { "en-US": "Welcome to Bailian CLI!", "zh-CN": "欢迎使用 Bailian CLI！" },
+  getStarted: { "en-US": "Get started in 2 steps:", "zh-CN": "只需两步即可开始使用：" },
+  getApiKey: { "en-US": "Get your API Key:", "zh-CN": "获取 API Key：" },
+  login: { "en-US": "Login:", "zh-CN": "登录：" },
+  tokenPlan: { "en-US": "Token Plan:", "zh-CN": "Token Plan：" },
+} satisfies Record<string, LocalizedText>;
+
+function localize(translator: Translator | undefined, text: LocalizedText): string {
+  return translator?.localize(text) ?? (typeof text === "string" ? text : text["en-US"]);
+}
+
+export function printWelcomeBanner(cliName: string, translator?: Translator): void {
   const color = ansi(process.stderr);
-  process.stderr.write(`\n  Welcome to ${color.purple("Bailian")} CLI!\n\n`);
-  process.stderr.write("  Get started in 2 steps:\n");
-  process.stderr.write(`  1. Get your API Key:  ${API_KEY_PAGE}\n`);
-  process.stderr.write(`  2. Login:             ${cliName} auth login --api-key <your-key>\n\n`);
-  process.stderr.write("  Token Plan:\n");
-  process.stderr.write(`  1. Get your API Key:  ${TOKEN_PLAN_PAGE}\n`);
+  const title = localize(translator, WELCOME_TEXT.title).replace(
+    "Bailian",
+    color.purple("Bailian"),
+  );
+  process.stderr.write(`\n  ${title}\n\n`);
+  process.stderr.write(`  ${localize(translator, WELCOME_TEXT.getStarted)}\n`);
+  process.stderr.write(`  1. ${localize(translator, WELCOME_TEXT.getApiKey)}  ${API_KEY_PAGE}\n`);
   process.stderr.write(
-    `  2. Login:             ${cliName} auth login --config token-plan --api-key <your-key>\n\n`,
+    `  2. ${localize(translator, WELCOME_TEXT.login)}             ${cliName} auth login --api-key <your-key>\n\n`,
+  );
+  process.stderr.write(`  ${localize(translator, WELCOME_TEXT.tokenPlan)}\n`);
+  process.stderr.write(
+    `  1. ${localize(translator, WELCOME_TEXT.getApiKey)}  ${TOKEN_PLAN_PAGE}\n`,
+  );
+  process.stderr.write(
+    `  2. ${localize(translator, WELCOME_TEXT.login)}             ${cliName} auth login --config token-plan --api-key <your-key>\n\n`,
   );
 }
 
diff --git a/packages/runtime/src/registry.ts b/packages/runtime/src/registry.ts
index 22ebd98..3b84480 100644
--- a/packages/runtime/src/registry.ts
+++ b/packages/runtime/src/registry.ts
@@ -1,4 +1,10 @@
-import type { AnyCommand, AuthRequirement, FlagDef, FlagsDef } from "bailian-cli-core";
+import type {
+  AnyCommand,
+  AuthRequirement,
+  FlagDef,
+  FlagsDef,
+  LocalizedText,
+} from "bailian-cli-core";
 import { UsageError } from "bailian-cli-core";
 import {
   CONSOLE_AUTH_FLAGS,
@@ -8,6 +14,8 @@ import {
   credentialFlagDefs,
 } from "bailian-cli-core";
 import { camelToKebab } from "./args.ts";
+import type { Translator } from "./i18n.ts";
+import { printWelcomeBanner } from "./output/banner.ts";
 import { ansi } from "./output/color.ts";
 
 export type { Command, AnyCommand, FlagDef, FlagsDef } from "bailian-cli-core";
@@ -25,6 +33,32 @@ interface CommandNode {
   children: Map<string, CommandNode>;
 }
 
+const HELP_TEXT = {
+  usage: { "en-US": "Usage:", "zh-CN": "用法：" },
+  commands: { "en-US": "Commands:", "zh-CN": "命令：" },
+  flags: { "en-US": "Flags:", "zh-CN": "选项：" },
+  globalFlags: { "en-US": "Global Flags:", "zh-CN": "全局选项：" },
+  modelAuthFlags: { "en-US": "Model Auth Flags:", "zh-CN": "模型鉴权选项：" },
+  modelAuthScope: { "en-US": "(model-domain commands)", "zh-CN": "（模型域命令）" },
+  consoleAuthFlags: { "en-US": "Console Auth Flags:", "zh-CN": "控制台鉴权选项：" },
+  consoleAuthScope: { "en-US": "(console-domain commands)", "zh-CN": "（控制台域命令）" },
+  openApiAuthFlags: { "en-US": "OpenAPI Auth Flags:", "zh-CN": "OpenAPI 鉴权选项：" },
+  openApiAuthScope: { "en-US": "(openapi-domain commands)", "zh-CN": "（OpenAPI 域命令）" },
+  gettingHelp: { "en-US": "Getting Help:", "zh-CN": "获取帮助：" },
+  gettingHelpDescription1: {
+    "en-US": "Add --help after any command to see its full list of flags, defaults,",
+    "zh-CN": "在任意命令后添加 --help，查看完整的选项和默认值，",
+  },
+  gettingHelpDescription2: {
+    "en-US": "and usage examples. For example:",
+    "zh-CN": "以及用法示例。例如：",
+  },
+  notes: { "en-US": "Notes:", "zh-CN": "说明：" },
+  examples: { "en-US": "Examples:", "zh-CN": "示例：" },
+  minimalWorkflow: { "en-US": "Minimal workflow.yaml:", "zh-CN": "最小 workflow.yaml：" },
+  tryIt: { "en-US": "Try it:", "zh-CN": "试一试：" },
+} satisfies Record<string, LocalizedText>;
+
 /**
  * What a command path resolves to in the registry. The single judgement that
  * feeds `resolve()` — no scattered `isGroupPath` + throwing `resolve`.
@@ -42,15 +76,21 @@ export class CommandRegistry {
   private root: CommandNode = { children: new Map() };
   /** Binary name shown in usage/help/error strings (e.g. "bl", "rag"). */
   private readonly cliName: string;
+  private readonly translator?: Translator;
   private readonly authRequirements = new Set<AuthRequirement>();
 
-  constructor(commands: Record<string, AnyCommand>, cliName: string) {
+  constructor(commands: Record<string, AnyCommand>, cliName: string, translator?: Translator) {
     this.cliName = cliName;
+    this.translator = translator;
     for (const [path, cmd] of Object.entries(commands)) {
       this.register(path, cmd);
     }
   }
 
+  private localize(text: LocalizedText): string {
+    return this.translator?.localize(text) ?? (typeof text === "string" ? text : text["en-US"]);
+  }
+
   private register(path: string, command: AnyCommand): void {
     // 同名守卫:命令自有 flag 不得与全局或其可见凭证域 flag 同名。
     const reserved = { ...GLOBAL_FLAGS, ...credentialFlagDefs(command) };
@@ -134,7 +174,8 @@ export class CommandRegistry {
     if (matched.length > 0 && node.children.size > 0) {
       const subcommands = Array.from(node.children.entries())
         .map(([name, n]) => {
-          if (n.command) return `  ${matched.join(" ")} ${name}    ${n.command.description}`;
+          if (n.command)
+            return `  ${matched.join(" ")} ${name}    ${this.localize(n.command.description)}`;
           const subs = Array.from(n.children.keys()).join(", ");
           return `  ${matched.join(" ")} ${name} [${subs}]`;
         })
@@ -164,7 +205,7 @@ export class CommandRegistry {
       for (const [name, child] of node.children) {
         const fullPath = prefix ? `${prefix} ${name}` : name;
         if (child.command) {
-          entries.push({ path: fullPath, desc: child.command.description });
+          entries.push({ path: fullPath, desc: this.localize(child.command.description) });
         }
         if (child.children.size > 0) {
           collect(child, fullPath);
@@ -184,7 +225,7 @@ export class CommandRegistry {
   ): string {
     const lines = Object.entries(defs).map(([k, def]) => ({
       flag: flagDisplay(k, def),
-      desc: def.description,
+      desc: this.localize(def.description),
     }));
     const maxLen = Math.max(...lines.map((l) => l.flag.length));
     return lines.map((l) => `  ${a(l.flag.padEnd(maxLen + 2))} ${d(l.desc)}`).join("\n");
@@ -231,8 +272,10 @@ export class CommandRegistry {
 
     // Group help (e.g. `bl auth --help`)
     const prefix = commandPath.join(" ");
-    out.write(`\n${this.bold("Usage:", out)} ${this.cliName} ${prefix} <command> [flags]\n\n`);
-    out.write(`${this.bold("Commands:", out)}\n`);
+    out.write(
+      `\n${this.bold(this.localize(HELP_TEXT.usage), out)} ${this.cliName} ${prefix} <command> [flags]\n\n`,
+    );
+    out.write(`${this.bold(this.localize(HELP_TEXT.commands), out)}\n`);
     this.printChildren(node, prefix, out);
     if (prefix === "pipeline") {
       this.printPipelineQuickStart(out);
@@ -240,12 +283,16 @@ export class CommandRegistry {
     out.write("\n");
   }
 
+  printWelcome(): void {
+    printWelcomeBanner(this.cliName, this.translator);
+  }
+
   private printPipelineQuickStart(out: NodeJS.WriteStream): void {
     const b = (s: string) => this.bold(s, out);
     const d = (s: string) => this.dim(s, out);
 
     out.write(`
-${b("Minimal workflow.yaml:")}
+${b(this.localize(HELP_TEXT.minimalWorkflow))}
 ${d("  version: workflow/v1")}
 ${d("  steps:")}
 ${d("    - id: chat")}
@@ -254,7 +301,7 @@ ${d("      input:")}
 ${d('        message: "Who are you?"')}
 ${d('        system: "You are a concise assistant."')}
 
-${b("Try it:")}
+${b(this.localize(HELP_TEXT.tryIt))}
 ${d(`  ${this.cliName} pipeline validate workflow.yaml`)}
 ${d(`  ${this.cliName} pipeline run workflow.yaml --dry-run --output json`)}
 `);
@@ -286,8 +333,8 @@ ${d(`  ${this.cliName} pipeline run workflow.yaml --dry-run --output json`)}
     const authFlagSections = [
       this.buildAuthFlagSection(
         "apiKey",
-        "Model Auth Flags:",
-        "(model-domain commands)",
+        this.localize(HELP_TEXT.modelAuthFlags),
+        this.localize(HELP_TEXT.modelAuthScope),
         MODEL_AUTH_FLAGS,
         b,
         a,
@@ -295,8 +342,8 @@ ${d(`  ${this.cliName} pipeline run workflow.yaml --dry-run --output json`)}
       ),
       this.buildAuthFlagSection(
         "console",
-        "Console Auth Flags:",
-        "(console-domain commands)",
+        this.localize(HELP_TEXT.consoleAuthFlags),
+        this.localize(HELP_TEXT.consoleAuthScope),
         CONSOLE_AUTH_FLAGS,
         b,
         a,
@@ -304,8 +351,8 @@ ${d(`  ${this.cliName} pipeline run workflow.yaml --dry-run --output json`)}
       ),
       this.buildAuthFlagSection(
         "openapi",
-        "OpenAPI Auth Flags:",
-        "(openapi-domain commands)",
+        this.localize(HELP_TEXT.openApiAuthFlags),
+        this.localize(HELP_TEXT.openApiAuthScope),
         OPENAPI_AUTH_FLAGS,
         b,
         a,
@@ -316,17 +363,17 @@ ${d(`  ${this.cliName} pipeline run workflow.yaml --dry-run --output json`)}
       .join("\n\n");
 
     out.write(`
-${b("Usage:")} ${this.cliName} <resource> <command> [flags]
+${b(this.localize(HELP_TEXT.usage))} ${this.cliName} <resource> <command> [flags]
 
-${b("Commands:")}
+${b(this.localize(HELP_TEXT.commands))}
 ${commandLines}
 
-${b("Global Flags:")}
+${b(this.localize(HELP_TEXT.globalFlags))}
 ${globalFlagLines}
 
-${authFlagSections ? `${authFlagSections}\n\n` : ""}${b("Getting Help:")}
-  ${d("Add --help after any command to see its full list of flags, defaults,")}
-  ${d("and usage examples. For example:")} ${this.cliName} ${this.helpExample()} --help
+${authFlagSections ? `${authFlagSections}\n\n` : ""}${b(this.localize(HELP_TEXT.gettingHelp))}
+  ${d(this.localize(HELP_TEXT.gettingHelpDescription1))}
+  ${d(this.localize(HELP_TEXT.gettingHelpDescription2))} ${this.cliName} ${this.helpExample()} --help
 `);
   }
 
@@ -339,33 +386,34 @@ ${authFlagSections ? `${authFlagSections}\n\n` : ""}${b("Getting Help:")}
     // same command shows the right invocation under any product (bl / rag / …).
     const prefix = [this.cliName, ...commandPath].join(" ");
 
-    out.write(`\n${cmd.description}\n`);
-    out.write(`${b("Usage:")} ${prefix}${cmd.usageArgs ? ` ${cmd.usageArgs}` : ""}\n`);
-    const flagEntries = [
-      ...Object.entries(cmd.flags ?? {}),
-      ...Object.entries(credentialFlagDefs(cmd)),
-    ] as [string, FlagDef][];
+    out.write(`\n${this.localize(cmd.description)}\n`);
+    out.write(
+      `${b(this.localize(HELP_TEXT.usage))} ${prefix}${cmd.usageArgs ? ` ${cmd.usageArgs}` : ""}\n`,
+    );
+    const ownFlagEntries = Object.entries(cmd.flags ?? {}) as [string, FlagDef][];
+    const credentialFlagEntries = Object.entries(credentialFlagDefs(cmd)) as [string, FlagDef][];
+    const flagEntries = [...ownFlagEntries, ...credentialFlagEntries];
     if (flagEntries.length > 0) {
-      const lines = flagEntries.map(([k, def]) => ({
-        flag: flagDisplay(k, def),
-        desc: def.description,
+      const lines = flagEntries.map(([key, def]) => ({
+        flag: flagDisplay(key, def),
+        desc: this.localize(def.description),
       }));
       const maxLen = Math.max(...lines.map((l) => l.flag.length));
-      out.write(`\n${b("Flags:")}\n`);
+      out.write(`\n${b(this.localize(HELP_TEXT.flags))}\n`);
       for (const l of lines) {
         out.write(`  ${a(l.flag.padEnd(maxLen + 2))} ${d(l.desc)}\n`);
       }
     }
-    out.write(`\n${b("Global Flags:")}\n`);
+    out.write(`\n${b(this.localize(HELP_TEXT.globalFlags))}\n`);
     out.write(this.buildFlagLines(GLOBAL_FLAGS, a, d) + "\n");
     if (cmd.notes && cmd.notes.length > 0) {
-      out.write(`\n${b("Notes:")}\n`);
+      out.write(`\n${b(this.localize(HELP_TEXT.notes))}\n`);
       for (const note of cmd.notes) {
         out.write(`  ${note}\n`);
       }
     }
     if (cmd.exampleArgs && cmd.exampleArgs.length > 0) {
-      out.write(`\n${b("Examples:")}\n`);
+      out.write(`\n${b(this.localize(HELP_TEXT.examples))}\n`);
       for (const ex of cmd.exampleArgs) {
         out.write(`  ${d(ex ? `${prefix} ${ex}` : prefix)}\n`);
       }
@@ -377,7 +425,10 @@ ${authFlagSections ? `${authFlagSections}\n\n` : ""}${b("Getting Help:")}
     const collect = (n: CommandNode, p: string) => {
       for (const [name, child] of n.children) {
         if (child.command)
-          entries.push({ fullName: `${p} ${name}`, description: child.command.description });
+          entries.push({
+            fullName: `${p} ${name}`,
+            description: this.localize(child.command.description),
+          });
         if (child.children.size > 0) collect(child, `${p} ${name}`);
       }
     };
diff --git a/packages/runtime/tests/i18n.test.ts b/packages/runtime/tests/i18n.test.ts
new file mode 100644
index 0000000..d49e83b
--- /dev/null
+++ b/packages/runtime/tests/i18n.test.ts
@@ -0,0 +1,61 @@
+import { expect, test } from "vite-plus/test";
+import { defineCommand } from "bailian-cli-core";
+import { createTranslator, type CliMessageBundle } from "../src/i18n.ts";
+import { CommandRegistry } from "../src/registry.ts";
+
+const messages = {
+  namespace: "test",
+  resources: {
+    "en-US": { greeting: "Hello, {{name}}!", englishOnly: "English fallback" },
+    "zh-CN": { greeting: "你好，{{name}}！" },
+  },
+} satisfies CliMessageBundle;
+
+test("translator uses the selected language, interpolation and English fallback", async () => {
+  const translator = await createTranslator("zh-CN", [messages]);
+
+  expect(translator.language).toBe("zh-CN");
+  expect(translator.translate("test:greeting", { name: "百炼" })).toBe("你好，百炼！");
+  expect(translator.translate("test:englishOnly")).toBe("English fallback");
+});
+
+test("translator resolves colocated text while preserving plain strings", async () => {
+  const translator = await createTranslator("zh-CN");
+
+  expect(translator.localize("Already localized")).toBe("Already localized");
+  expect(
+    translator.localize({
+      "en-US": "Show help",
+      "zh-CN": "显示帮助信息",
+    }),
+  ).toBe("显示帮助信息");
+});
+
+test("registry renders runtime help copy with the selected language", async () => {
+  const translator = await createTranslator("zh-CN");
+  const command = defineCommand({
+    description: {
+      "en-US": "Test command",
+      "zh-CN": "测试命令",
+    },
+    auth: "none",
+    run: async () => {},
+  });
+  const registry = new CommandRegistry({ test: command }, "bl", translator);
+  let output = "";
+  const stream = {
+    isTTY: false,
+    write(chunk: string) {
+      output += chunk;
+      return true;
+    },
+  } as NodeJS.WriteStream;
+
+  registry.printHelp([], stream);
+
+  expect(output).toContain("用法： bl <resource> <command> [flags]");
+  expect(output).toContain("测试命令");
+  expect(output).toContain("全局选项：");
+  expect(output).toContain("显示帮助信息");
+  expect(output).toContain("获取帮助：");
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index eb698a3..815a16f 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -24,12 +24,15 @@ catalogs:
     chalk:
       specifier: ^5.6.2
       version: 5.6.2
-    tar-stream:
-      specifier: ^3.2.0
-      version: 3.2.0
+    i18next:
+      specifier: ^26.3.6
+      version: 26.3.6
     smol-toml:
       specifier: ^1.4.2
       version: 1.7.0
+    tar-stream:
+      specifier: ^3.2.0
+      version: 3.2.0
     tsx:
       specifier: ^4.23.0
       version: 4.23.0
@@ -254,6 +257,9 @@ importers:
       chalk:
         specifier: 'catalog:'
         version: 5.6.2
+      i18next:
+        specifier: 'catalog:'
+        version: 26.3.6(typescript@6.0.3)
       undici:
         specifier: 'catalog:'
         version: 6.27.0
@@ -1200,6 +1206,14 @@ packages:
     resolution: {integrity: sha512-QRbvDIbx6YklUe6RxeTeleMR0yv3cYH6PsPZHcnVn7xv7zO1BHN8r0XETu8n6Ye3Q+ahtSarc3WgtNWmehIBfA==}
     engines: {node: '>=18'}
 
+  i18next@26.3.6:
+    resolution: {integrity: sha512-Bu5Z2nAXgfVyM8xvW3jk9EKRIuX37PudsrBViThNFx7CR7aaYTpP01cxNB/E4c4UUzTDiAZRstEhsRfPOL/8xA==}
+    peerDependencies:
+      typescript: ^5 || ^6 || ^7
+    peerDependenciesMeta:
+      typescript:
+        optional: true
+
   immediate@3.0.6:
     resolution: {integrity: sha512-XXOFtyqDjNDAQxVfYxuF7g9Il/IbWmmlQg2MYKOH8ExIT1qg6xc4zyS3HaEEATgs1btfzxq15ciUiY7gjSXRGQ==}
 
@@ -2250,6 +2264,10 @@ snapshots:
 
   get-east-asian-width@1.6.0: {}
 
+  i18next@26.3.6(typescript@6.0.3):
+    optionalDependencies:
+      typescript: 6.0.3
+
   immediate@3.0.6: {}
 
   inherits@2.0.4: {}
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
index 611df31..3ce8416 100644
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@@ -9,6 +9,7 @@ catalog:
   ajv: ^8.20.0
   boxen: ^8.0.1
   chalk: ^5.6.2
+  i18next: ^26.3.6
   tar-stream: ^3.2.0
   smol-toml: ^1.4.2
   tsx: ^4.23.0
diff --git a/skills/bailian-cli/reference/config.md b/skills/bailian-cli/reference/config.md
index 50403b9..649eb6f 100644
--- a/skills/bailian-cli/reference/config.md
+++ b/skills/bailian-cli/reference/config.md
@@ -85,13 +85,17 @@ bl config list --output json
 
 #### Flags
 
-| Flag              | Type   | Required | Description                                                                                                                                                  |
-| ----------------- | ------ | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ |
-| `--key <key>`     | string | yes      | Config key (base*url, output, output_dir, timeout, api_key, access_token, access_key_id, access_key_secret, security_token, default*\*\_model, workspace_id) |
-| `--value <value>` | string | yes      | Value to set                                                                                                                                                 |
+| Flag              | Type   | Required | Description                                                                                                                                                            |
+| ----------------- | ------ | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `--key <key>`     | string | yes      | Config key (language, base*url, output, output_dir, timeout, api_key, access_token, access_key_id, access_key_secret, security_token, default*\*\_model, workspace_id) |
+| `--value <value>` | string | yes      | Value to set                                                                                                                                                           |
 
 #### Examples
 
+```bash
+bl config set --key language --value zh-CN
+```
+
 ```bash
 bl config set --key output --value json
 ```
diff --git a/tools/generate-reference.ts b/tools/generate-reference.ts
index 976d80a..a9f4b46 100644
--- a/tools/generate-reference.ts
+++ b/tools/generate-reference.ts
@@ -25,6 +25,7 @@ import {
   type AnyCommand,
   type FlagDef,
   type FlagsDef,
+  type LocalizedText,
 } from "../packages/core/src/index.ts";
 import { commands } from "../packages/cli/src/commands.ts";
 
@@ -62,6 +63,11 @@ function escCell(s: string): string {
   return s.replace(/\|/g, "\\|").replace(/\n/g, " ").trim();
 }
 
+/** Skill references are English artifacts; localized CLI text keeps English here. */
+function referenceText(text: LocalizedText): string {
+  return typeof text === "string" ? text : text["en-US"];
+}
+
 function topLevel(path: string): string {
   return path.split(" ")[0]!;
 }
@@ -88,7 +94,7 @@ function formatFlagsTable(flags: FlagsDef | undefined): string {
   if (!entries.length) return "_No command-specific flags._\n";
   const rows = entries.map(([key, def]) => {
     const req = def.type !== "switch" && def.required ? "yes" : "no";
-    return `| \`${escCell(flagDisplay(key, def))}\` | ${escCell(flagType(def))} | ${req} | ${escCell(def.description)} |`;
+    return `| \`${escCell(flagDisplay(key, def))}\` | ${escCell(flagType(def))} | ${req} | ${escCell(referenceText(def.description))} |`;
   });
   return [
     "| Flag | Type | Required | Description |",
@@ -118,7 +124,7 @@ function commandSection(path: string, cmd: AnyCommand): string {
   lines.push(`### \`bl ${path}\``, "");
   lines.push(`| Field | Value |`, `| --- | --- |`);
   lines.push(`| **Name** | \`${escCell(path)}\` |`);
-  lines.push(`| **Description** | ${escCell(cmd.description)} |`);
+  lines.push(`| **Description** | ${escCell(referenceText(cmd.description))} |`);
   // Commands store argument-only usage; the `bl <path>` prefix is added here.
   const usage = `bl ${path}${cmd.usageArgs ? ` ${cmd.usageArgs}` : ""}`;
   lines.push(`| **Usage** | \`${escCell(usage)}\` |`);
@@ -172,7 +178,7 @@ function buildGroupFile(group: string, groupEntries: [string, AnyCommand][]): st
   ];
 
   for (const [path, cmd] of groupEntries) {
-    lines.push(`| \`bl ${path}\` | ${escCell(cmd.description)} |`);
+    lines.push(`| \`bl ${path}\` | ${escCell(referenceText(cmd.description))} |`);
   }
 
   lines.push("", "## Command details", "");
@@ -205,7 +211,9 @@ function buildIndex(
 
   for (const [path, cmd] of entries) {
     const group = topLevel(path);
-    lines.push(`| \`bl ${path}\` | ${escCell(cmd.description)} | [${group}.md](${group}.md) |`);
+    lines.push(
+      `| \`bl ${path}\` | ${escCell(referenceText(cmd.description))} | [${group}.md](${group}.md) |`,
+    );
   }
 
   lines.push("", "## By group", "", "| Group | Commands | Reference |", "| --- | --- | --- |");