diff --git a/lib/index.d.ts b/lib/index.d.ts
index da367a91..3ed262ea 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -26,7 +26,7 @@ declare namespace Joi {
 
     type BasicType = boolean | number | string | any[] | object | null;
 
-    type LanguageMessages = Record<string, string>;
+    type LanguageMessages = Record<string, string | Record<string, string>>;
 
     type PresenceMode = 'optional' | 'required' | 'forbidden';