diff --git a/packages/kilo-vscode/tests/unit/language-utils.test.ts b/packages/kilo-vscode/tests/unit/language-utils.test.ts
new file mode 100644
index 00000000000..75ad9bd5f8c
--- /dev/null
+++ b/packages/kilo-vscode/tests/unit/language-utils.test.ts
@@ -0,0 +1,94 @@
+import { describe, it, expect } from "bun:test"
+import { normalizeLocale, resolveTemplate } from "../../webview-ui/src/context/language-utils"
+
+describe("normalizeLocale", () => {
+  it("returns 'en' for English", () => {
+    expect(normalizeLocale("en")).toBe("en")
+    expect(normalizeLocale("en-US")).toBe("en")
+    expect(normalizeLocale("en-GB")).toBe("en")
+  })
+
+  it("returns 'zh' for Simplified Chinese", () => {
+    expect(normalizeLocale("zh")).toBe("zh")
+    expect(normalizeLocale("zh-CN")).toBe("zh")
+    expect(normalizeLocale("zh-Hans")).toBe("zh")
+  })
+
+  it("returns 'zht' for Traditional Chinese", () => {
+    expect(normalizeLocale("zh-Hant")).toBe("zht")
+    expect(normalizeLocale("zh-TW")).toBe("zh")
+    expect(normalizeLocale("zh-hant-TW")).toBe("zht")
+  })
+
+  it("returns 'de' for German", () => {
+    expect(normalizeLocale("de")).toBe("de")
+    expect(normalizeLocale("de-AT")).toBe("de")
+  })
+
+  it("returns 'ko' for Korean", () => {
+    expect(normalizeLocale("ko")).toBe("ko")
+    expect(normalizeLocale("ko-KR")).toBe("ko")
+  })
+
+  it("returns 'no' for Norwegian Bokmål", () => {
+    expect(normalizeLocale("nb")).toBe("no")
+    expect(normalizeLocale("nb-NO")).toBe("no")
+  })
+
+  it("returns 'no' for Norwegian Nynorsk", () => {
+    expect(normalizeLocale("nn")).toBe("no")
+  })
+
+  it("returns 'br' for Portuguese", () => {
+    expect(normalizeLocale("pt")).toBe("br")
+    expect(normalizeLocale("pt-BR")).toBe("br")
+    expect(normalizeLocale("pt-PT")).toBe("br")
+  })
+
+  it("falls back to 'en' for unknown locale", () => {
+    expect(normalizeLocale("xx")).toBe("en")
+    expect(normalizeLocale("xyz-ZZ")).toBe("en")
+  })
+
+  it("is case-insensitive", () => {
+    expect(normalizeLocale("EN")).toBe("en")
+    expect(normalizeLocale("DE")).toBe("de")
+    expect(normalizeLocale("ZH-HANT")).toBe("zht")
+  })
+})
+
+describe("resolveTemplate", () => {
+  it("returns text unchanged when no params", () => {
+    expect(resolveTemplate("hello world")).toBe("hello world")
+  })
+
+  it("returns text unchanged when params is undefined", () => {
+    expect(resolveTemplate("no {{var}} here", undefined)).toBe("no {{var}} here")
+  })
+
+  it("interpolates a single variable", () => {
+    expect(resolveTemplate("Hello {{name}}!", { name: "World" })).toBe("Hello World!")
+  })
+
+  it("interpolates multiple variables", () => {
+    const result = resolveTemplate("{{a}} + {{b}} = {{c}}", { a: "1", b: "2", c: "3" })
+    expect(result).toBe("1 + 2 = 3")
+  })
+
+  it("replaces missing variable with empty string", () => {
+    expect(resolveTemplate("{{missing}}", {})).toBe("")
+  })
+
+  it("handles numeric variable values", () => {
+    expect(resolveTemplate("count: {{n}}", { n: 42 })).toBe("count: 42")
+  })
+
+  it("handles whitespace around key in braces", () => {
+    expect(resolveTemplate("{{ name }}", { name: "test" })).toBe("test")
+  })
+
+  it("leaves unrelated text intact", () => {
+    const result = resolveTemplate("prefix {{x}} suffix", { x: "VALUE" })
+    expect(result).toBe("prefix VALUE suffix")
+  })
+})
diff --git a/packages/kilo-vscode/webview-ui/src/context/language-utils.ts b/packages/kilo-vscode/webview-ui/src/context/language-utils.ts
new file mode 100644
index 00000000000..46b6b04f792
--- /dev/null
+++ b/packages/kilo-vscode/webview-ui/src/context/language-utils.ts
@@ -0,0 +1,70 @@
+export type Locale =
+  | "en"
+  | "zh"
+  | "zht"
+  | "ko"
+  | "de"
+  | "es"
+  | "fr"
+  | "da"
+  | "ja"
+  | "pl"
+  | "ru"
+  | "ar"
+  | "no"
+  | "br"
+  | "th"
+  | "bs"
+
+export const LOCALES: readonly Locale[] = [
+  "en",
+  "zh",
+  "zht",
+  "ko",
+  "de",
+  "es",
+  "fr",
+  "da",
+  "ja",
+  "pl",
+  "ru",
+  "ar",
+  "no",
+  "br",
+  "th",
+  "bs",
+]
+
+/**
+ * Normalize a BCP 47 language tag to one of the supported Locale values.
+ * Falls back to "en" for unrecognized locales.
+ */
+export function normalizeLocale(lang: string): Locale {
+  const lower = lang.toLowerCase()
+  if (lower.startsWith("zh")) {
+    return lower.includes("hant") ? "zht" : "zh"
+  }
+  for (const loc of LOCALES) {
+    if (lower.startsWith(loc)) {
+      return loc
+    }
+  }
+  if (lower.startsWith("nb") || lower.startsWith("nn")) {
+    return "no"
+  }
+  if (lower.startsWith("pt")) {
+    return "br"
+  }
+  return "en"
+}
+
+/**
+ * Perform {{key}} template interpolation against a params record.
+ */
+export function resolveTemplate(text: string, params?: Record<string, string | number | boolean | undefined>): string {
+  if (!params) return text
+  return text.replace(/\{\{\s*([^}]+?)\s*\}\}/g, (_, rawKey) => {
+    const value = params[String(rawKey)]
+    return value === undefined ? "" : String(value)
+  })
+}
diff --git a/packages/kilo-vscode/webview-ui/src/context/language.tsx b/packages/kilo-vscode/webview-ui/src/context/language.tsx
index ae2bb645535..2fd2d631222 100644
--- a/packages/kilo-vscode/webview-ui/src/context/language.tsx
+++ b/packages/kilo-vscode/webview-ui/src/context/language.tsx
@@ -58,43 +58,12 @@ import { dict as kiloBr } from "@kilocode/kilo-i18n/br"
 import { dict as kiloTh } from "@kilocode/kilo-i18n/th"
 import { dict as kiloBs } from "@kilocode/kilo-i18n/bs"
 import { useVSCode } from "./vscode"
+import { normalizeLocale as _normalizeLocale, resolveTemplate as _resolveTemplate } from "./language-utils"
 
-export type Locale =
-  | "en"
-  | "zh"
-  | "zht"
-  | "ko"
-  | "de"
-  | "es"
-  | "fr"
-  | "da"
-  | "ja"
-  | "pl"
-  | "ru"
-  | "ar"
-  | "no"
-  | "br"
-  | "th"
-  | "bs"
-
-export const LOCALES: readonly Locale[] = [
-  "en",
-  "zh",
-  "zht",
-  "ko",
-  "de",
-  "es",
-  "fr",
-  "da",
-  "ja",
-  "pl",
-  "ru",
-  "ar",
-  "no",
-  "br",
-  "th",
-  "bs",
-]
+export type { Locale } from "./language-utils"
+export { LOCALES } from "./language-utils"
+import type { Locale } from "./language-utils"
+import { LOCALES } from "./language-utils"
 
 export const LOCALE_LABELS: Record<Locale, string> = {
   en: "English",
@@ -137,33 +106,11 @@ const dicts: Record<Locale, Record<string, string>> = {
 }
 
 function normalizeLocale(lang: string): Locale {
-  const lower = lang.toLowerCase()
-  if (lower.startsWith("zh")) {
-    return lower.includes("hant") ? "zht" : "zh"
-  }
-  for (const loc of LOCALES) {
-    if (lower.startsWith(loc)) {
-      return loc
-    }
-  }
-  // Special cases
-  if (lower.startsWith("nb") || lower.startsWith("nn")) {
-    return "no"
-  }
-  if (lower.startsWith("pt")) {
-    return "br"
-  }
-  return "en"
+  return _normalizeLocale(lang)
 }
 
 function resolveTemplate(text: string, params?: UiI18nParams) {
-  if (!params) {
-    return text
-  }
-  return text.replace(/\{\{\s*([^}]+?)\s*\}\}/g, (_, rawKey) => {
-    const value = params[String(rawKey)]
-    return value === undefined ? "" : String(value)
-  })
+  return _resolveTemplate(text, params as Record<string, string | number | boolean | undefined>)
 }
 
 interface LanguageProviderProps {