diff --git a/lightrag/prompt.py b/lightrag/prompt.py
index bf514fe8..64e105c2 100644
--- a/lightrag/prompt.py
+++ b/lightrag/prompt.py
@@ -374,6 +374,7 @@ Given a user query, your task is to extract two distinct types of keywords:
 2. **Source of Truth**: All keywords must be explicitly derived from the user query, with both high-level and low-level keyword categories are required to contain content.
 3. **Concise & Meaningful**: Keywords should be concise words or meaningful phrases. Prioritize multi-word phrases when they represent a single concept. For example, from "latest financial report of Apple Inc.", you should extract "latest financial report" and "Apple Inc." rather than "latest", "financial", "report", and "Apple".
 4. **Handle Edge Cases**: For queries that are too simple, vague, or nonsensical (e.g., "hello", "ok", "asdfghjkl"), you must return a JSON object with empty lists for both keyword types.
+5. **Language**: All extracted keywords MUST be in {language}. Proper nouns (e.g., personal names, place names, organization names) should be kept in their original language.
 
 ---Examples---
 {examples}