diff --git a/ui/.build/src/i18n.ts b/ui/.build/src/i18n.ts
index 19b1f5ade9b6..ef557da09a4d 100644
--- a/ui/.build/src/i18n.ts
+++ b/ui/.build/src/i18n.ts
@@ -18,13 +18,13 @@ const isFormat = /%(?:[\d]\$)?s/;
 
 const tsPrelude = `// Generated
 interface I18nFormat {
-  (...args: (string | number)[]): string;
-  asArray: <T>(...args: T[]) => (T | string)[], // vdom
+  (...args: (string | number)[]): string; // formatted
+  asArray: <T>(...args: T[]) => (T | string)[]; // vdom
 }
 interface I18nPlural {
-  (quantity: number, ...args: (string | number)[]): string, // pluralSame
-  raw: (quantity: number, ...args: (string | number)[]) => string, // plural
-  asArray: <T>(quantity: number, ...args: T[]) => (T | string)[], // vdomPlural
+  (quantity: number, ...args: (string | number)[]): string; // pluralSame
+  raw: (quantity: number, ...args: (string | number)[]) => string; // plural
+  asArray: <T>(quantity: number, ...args: T[]) => (T | string)[]; // vdomPlural
 }
 interface I18n {
   /** Global noarg key lookup (only if absolutely necessary). */
@@ -98,8 +98,9 @@ export async function i18n(isBoot = true): Promise<void> {
 }
 
 async function compileTypings(): Promise<void> {
+  const typingsPathname = path.join(env.typesDir, 'lichess', `i18n.d.ts`);
   const [tstat] = await Promise.all([
-    fs.promises.stat(path.join(env.typesDir, 'lichess', `i18n.d.ts`)).catch(() => undefined),
+    fs.promises.stat(typingsPathname).catch(() => undefined),
     fs.promises.mkdir(env.i18nJsDir).catch(() => {}),
   ]);
   const catStats = await Promise.all(cats.map(d => updated(d)));
@@ -114,24 +115,32 @@ async function compileTypings(): Promise<void> {
         ),
       ),
     );
-    const code =
+    await fs.promises.writeFile(
+      typingsPathname,
       tsPrelude +
-      [...dicts]
-        .map(
-          ([cat, dict]) =>
-            `  ${cat}: {\n` +
-            [...dict.entries()]
-              .map(([k, v]) => {
-                const tpe = typeof v !== 'string' ? 'I18nPlural' : isFormat.test(v) ? 'I18nFormat' : 'string';
-                const comment = typeof v === 'string' ? v.split('\n')[0] : v['other']?.split('\n')[0];
-                return `    /** ${comment} */\n    ${k}: ${tpe};`;
-              })
-              .join('\n') +
-            '\n  };\n',
-        )
-        .join('') +
-      '}\n';
-    return fs.promises.writeFile(path.join(env.typesDir, 'lichess', `i18n.d.ts`), code);
+        [...dicts]
+          .map(
+            ([cat, dict]) =>
+              `  ${cat}: {\n` +
+              [...dict.entries()]
+                .map(([k, v]) => {
+                  if (!/^[A-Za-z_]\w*$/.test(k)) k = `'${k}'`;
+                  const tpe =
+                    typeof v !== 'string' ? 'I18nPlural' : isFormat.test(v) ? 'I18nFormat' : 'string';
+                  const comment = typeof v === 'string' ? v.split('\n')[0] : v['other']?.split('\n')[0];
+                  return `    /** ${comment} */\n    ${k}: ${tpe};`;
+                })
+                .join('\n') +
+              '\n  };\n',
+          )
+          .join('') +
+        '}\n',
+    );
+    const mstat = catStats.reduce(
+      (a, b) => (a && b && quantize(a.mtimeMs) > quantize(b.mtimeMs) ? a : b),
+      tstat || false,
+    );
+    if (mstat) await fs.promises.utimes(typingsPathname, mstat.mtime, mstat.mtime);
   }
 }
 
@@ -205,7 +214,7 @@ async function updated(cat: string, locale?: string): Promise<fs.Stats | false>
   const jsPath = path.join(env.i18nJsDir, `${cat}.${locale ?? 'en-GB'}.js`);
   const [xml, js] = await Promise.allSettled([fs.promises.stat(xmlPath), fs.promises.stat(jsPath)]);
   return xml.status === 'rejected' ||
-    (js.status !== 'rejected' && quantize(xml.value.mtimeMs, 2000) <= quantize(js.value.mtimeMs, 2000))
+    (js.status !== 'rejected' && quantize(xml.value.mtimeMs) <= quantize(js.value.mtimeMs))
     ? false
     : xml.value;
 }
diff --git a/ui/@types/lichess/i18n.d.ts b/ui/@types/lichess/i18n.d.ts
index 376e7f58087d..6ac9d4d23994 100644
--- a/ui/@types/lichess/i18n.d.ts
+++ b/ui/@types/lichess/i18n.d.ts
@@ -1,6 +1,6 @@
 // Generated
 interface I18nFormat {
-  (...args: (string | number)[]): string;
+  (...args: (string | number)[]): string; // formatted
   asArray: <T>(...args: T[]) => (T | string)[]; // vdom
 }
 interface I18nPlural {