diff --git a/ui/src/i18n/locales/en-US.ts b/ui/src/i18n/locales/en-US.ts
index 99346320d..60e268ec4 100644
--- a/ui/src/i18n/locales/en-US.ts
+++ b/ui/src/i18n/locales/en-US.ts
@@ -687,6 +687,33 @@ export const enUS = {
     light: "Light",
     dark: "Dark",
     system: "System",
+    ariaLabel: "Theme",
+    systemAriaLabel: "System theme",
+    lightAriaLabel: "Light theme",
+    darkAriaLabel: "Dark theme",
+  },
+
+  // Chat controls
+  chatControls: {
+    disabledDuringOnboarding: "Disabled during onboarding",
+    toggleThinking: "Toggle assistant thinking/working output",
+    toggleFocusMode: "Toggle focus mode (hide sidebar + page header)",
+    selectLanguage: "Select language",
+  },
+
+  // Gateway connection
+  gateway: {
+    disconnected: "Disconnected from gateway.",
+  },
+
+  // Nostr profile messages
+  nostrProfile: {
+    publishFailed: "Profile publish failed on all relays.",
+    publishSuccess: "Profile published to relays.",
+    updateFailed: "Profile update failed",
+    importFailed: "Profile import failed",
+    importedFromRelays: "Profile imported from relays. Review and publish.",
+    importedReviewPublish: "Profile imported. Review and publish.",
   },
 
   // Time/date formatting
diff --git a/ui/src/i18n/locales/zh-TW.ts b/ui/src/i18n/locales/zh-TW.ts
index 88cde04d6..ba43dfeff 100644
--- a/ui/src/i18n/locales/zh-TW.ts
+++ b/ui/src/i18n/locales/zh-TW.ts
@@ -694,6 +694,33 @@ export const zhTW = {
     light: "淺色",
     dark: "深色",
     system: "跟隨系統",
+    ariaLabel: "主題",
+    systemAriaLabel: "跟隨系統主題",
+    lightAriaLabel: "淺色主題",
+    darkAriaLabel: "深色主題",
+  },
+
+  // 對話控制
+  chatControls: {
+    disabledDuringOnboarding: "引導期間已停用",
+    toggleThinking: "切換助手思考/工作輸出",
+    toggleFocusMode: "切換專注模式（隱藏側邊欄和頁首）",
+    selectLanguage: "選擇語言",
+  },
+
+  // 閘道器連線
+  gateway: {
+    disconnected: "已與閘道器斷線。",
+  },
+
+  // Nostr 個人檔案訊息
+  nostrProfile: {
+    publishFailed: "個人檔案發布至所有中繼站失敗。",
+    publishSuccess: "個人檔案已發布至中繼站。",
+    updateFailed: "個人檔案更新失敗",
+    importFailed: "個人檔案匯入失敗",
+    importedFromRelays: "已從中繼站匯入個人檔案。請檢視並發布。",
+    importedReviewPublish: "已匯入個人檔案。請檢視並發布。",
   },
 
   // 時間/日期格式
diff --git a/ui/src/ui/app-channels.ts b/ui/src/ui/app-channels.ts
index 91ff734ed..193a8ad9c 100644
--- a/ui/src/ui/app-channels.ts
+++ b/ui/src/ui/app-channels.ts
@@ -8,6 +8,7 @@ import { loadConfig, saveConfig } from "./controllers/config";
 import type { MoltbotApp } from "./app";
 import type { NostrProfile } from "./types";
 import { createNostrProfileFormState } from "./views/channels.nostr-profile-form";
+import { t } from "../i18n";
 
 export async function handleWhatsAppStart(host: MoltbotApp, force: boolean) {
   await startWhatsAppLogin(host, force);
@@ -142,7 +143,7 @@ export async function handleNostrProfileSave(host: MoltbotApp) {
       host.nostrProfileFormState = {
         ...state,
         saving: false,
-        error: "Profile publish failed on all relays.",
+        error: t("nostrProfile.publishFailed"),
         success: null,
       };
       return;
@@ -152,7 +153,7 @@ export async function handleNostrProfileSave(host: MoltbotApp) {
       ...state,
       saving: false,
       error: null,
-      success: "Profile published to relays.",
+      success: t("nostrProfile.publishSuccess"),
       fieldErrors: {},
       original: { ...state.values },
     };
@@ -161,7 +162,7 @@ export async function handleNostrProfileSave(host: MoltbotApp) {
     host.nostrProfileFormState = {
       ...state,
       saving: false,
-      error: `Profile update failed: ${String(err)}`,
+      error: `${t("nostrProfile.updateFailed")}: ${String(err)}`,
       success: null,
     };
   }
@@ -214,8 +215,8 @@ export async function handleNostrProfileImport(host: MoltbotApp) {
       values: nextValues,
       error: null,
       success: data.saved
-        ? "Profile imported from relays. Review and publish."
-        : "Profile imported. Review and publish.",
+        ? t("nostrProfile.importedFromRelays")
+        : t("nostrProfile.importedReviewPublish"),
       showAdvanced,
     };
 
@@ -226,7 +227,7 @@ export async function handleNostrProfileImport(host: MoltbotApp) {
     host.nostrProfileFormState = {
       ...state,
       importing: false,
-      error: `Profile import failed: ${String(err)}`,
+      error: `${t("nostrProfile.importFailed")}: ${String(err)}`,
       success: null,
     };
   }
diff --git a/ui/src/ui/app-render.helpers.ts b/ui/src/ui/app-render.helpers.ts
index da0d26bfc..dfb03d3dc 100644
--- a/ui/src/ui/app-render.helpers.ts
+++ b/ui/src/ui/app-render.helpers.ts
@@ -107,8 +107,8 @@ export function renderChatControls(state: AppViewState) {
         }}
         aria-pressed=${showThinking}
         title=${disableThinkingToggle
-          ? "Disabled during onboarding"
-          : "Toggle assistant thinking/working output"}
+          ? t("chatControls.disabledDuringOnboarding")
+          : t("chatControls.toggleThinking")}
       >
         ${icons.brain}
       </button>
@@ -124,8 +124,8 @@ export function renderChatControls(state: AppViewState) {
         }}
         aria-pressed=${focusActive}
         title=${disableFocusToggle
-          ? "Disabled during onboarding"
-          : "Toggle focus mode (hide sidebar + page header)"}
+          ? t("chatControls.disabledDuringOnboarding")
+          : t("chatControls.toggleFocusMode")}
       >
         ${focusIcon}
       </button>
@@ -172,14 +172,14 @@ export function renderThemeToggle(state: AppViewState) {
 
   return html`
     <div class="theme-toggle" style="--theme-index: ${index};">
-      <div class="theme-toggle__track" role="group" aria-label="Theme">
+      <div class="theme-toggle__track" role="group" aria-label="${t("theme.ariaLabel")}">
         <span class="theme-toggle__indicator"></span>
         <button
           class="theme-toggle__button ${state.theme === "system" ? "active" : ""}"
           @click=${applyTheme("system")}
           aria-pressed=${state.theme === "system"}
-          aria-label="System theme"
-          title="System"
+          aria-label="${t("theme.systemAriaLabel")}"
+          title="${t("theme.system")}"
         >
           ${renderMonitorIcon()}
         </button>
@@ -187,8 +187,8 @@ export function renderThemeToggle(state: AppViewState) {
           class="theme-toggle__button ${state.theme === "light" ? "active" : ""}"
           @click=${applyTheme("light")}
           aria-pressed=${state.theme === "light"}
-          aria-label="Light theme"
-          title="Light"
+          aria-label="${t("theme.lightAriaLabel")}"
+          title="${t("theme.light")}"
         >
           ${renderSunIcon()}
         </button>
@@ -196,8 +196,8 @@ export function renderThemeToggle(state: AppViewState) {
           class="theme-toggle__button ${state.theme === "dark" ? "active" : ""}"
           @click=${applyTheme("dark")}
           aria-pressed=${state.theme === "dark"}
-          aria-label="Dark theme"
-          title="Dark"
+          aria-label="${t("theme.darkAriaLabel")}"
+          title="${t("theme.dark")}"
         >
           ${renderMoonIcon()}
         </button>
@@ -263,7 +263,7 @@ export function renderLanguageSwitcher() {
         class="language-switcher__select"
         .value=${currentLocale}
         @change=${handleChange}
-        aria-label="Select language"
+        aria-label="${t("chatControls.selectLanguage")}"
       >
         ${locales.map(
           (locale) => html`
diff --git a/ui/src/ui/app-render.ts b/ui/src/ui/app-render.ts
index e7567d3e3..79983aa44 100644
--- a/ui/src/ui/app-render.ts
+++ b/ui/src/ui/app-render.ts
@@ -106,7 +106,7 @@ export function renderApp(state: AppViewState) {
   const presenceCount = state.presenceEntries.length;
   const sessionsCount = state.sessionsResult?.count ?? null;
   const cronNext = state.cronStatus?.nextWakeAtMs ?? null;
-  const chatDisabledReason = state.connected ? null : "Disconnected from gateway.";
+  const chatDisabledReason = state.connected ? null : t("gateway.disconnected");
   const isChat = state.tab === "chat";
   const chatFocus = isChat && (state.settings.chatFocusMode || state.onboarding);
   const showThinking = state.onboarding ? false : state.settings.chatShowThinking;