diff --git a/src/i18n/request.ts b/src/i18n/request.ts
index e5eb20991c..0533cbed84 100644
--- a/src/i18n/request.ts
+++ b/src/i18n/request.ts
@@ -3,23 +3,57 @@ import { cookies, headers } from "next/headers";
 import { LOCALES, DEFAULT_LOCALE, LOCALE_COOKIE } from "./config";
 import type { Locale } from "./config";
 
+const FALLBACK_LOCALE = "en";
+
+/**
+ * Deep merge that mutates `target` with values from `source`.
+ * If both have an object at the same key, recurse.
+ * Otherwise prefer the existing value in `target` (locale-specific wins).
+ */
+export function deepMergeFallback(
+  target: Record<string, unknown>,
+  source: Record<string, unknown>
+): Record<string, unknown> {
+  for (const [key, sourceValue] of Object.entries(source)) {
+    const targetValue = target[key];
+    if (
+      sourceValue !== null &&
+      typeof sourceValue === "object" &&
+      !Array.isArray(sourceValue) &&
+      targetValue !== null &&
+      typeof targetValue === "object" &&
+      !Array.isArray(targetValue)
+    ) {
+      deepMergeFallback(targetValue as Record<string, unknown>, sourceValue as Record<string, unknown>);
+    } else if (targetValue === undefined) {
+      target[key] = sourceValue;
+    }
+  }
+  return target;
+}
+
 export default getRequestConfig(async () => {
-  // 1. Try cookie
   const cookieStore = await cookies();
   let locale: string = cookieStore.get(LOCALE_COOKIE)?.value || "";
 
-  // 2. Try custom header (set by middleware)
   if (!locale) {
     const headerStore = await headers();
     locale = headerStore.get("x-locale") || "";
   }
 
-  // 3. Validate & fallback
   if (!LOCALES.includes(locale as Locale)) {
     locale = DEFAULT_LOCALE;
   }
 
-  const messages = (await import(`./messages/${locale}.json`)).default;
+  const localeMessages = (await import(`./messages/${locale}.json`)).default;
+
+  // G1: fall back to EN for any missing key. EN is loaded only once per request
+  // and only when the active locale is not EN itself (no-op).
+  let messages = localeMessages as Record<string, unknown>;
+  if (locale !== FALLBACK_LOCALE) {
+    const fallbackMessages = (await import(`./messages/${FALLBACK_LOCALE}.json`)).default as Record<string, unknown>;
+    messages = deepMergeFallback({ ...localeMessages }, fallbackMessages);
+  }
 
   return {
     locale,