diff --git a/aider/coders/editblock_prompts.py b/aider/coders/editblock_prompts.py
index 075c9c71d..08b985089 100644
--- a/aider/coders/editblock_prompts.py
+++ b/aider/coders/editblock_prompts.py
@@ -11,6 +11,8 @@ Respect and use existing conventions, libraries, etc that are already present in
 Take requests for changes to the supplied code.
 If the request is ambiguous, ask questions.
 
+Always reply to the user in the same language they are using.
+
 Once you understand the request you MUST:
 1. List the files you need to modify. Only suggest changes to files that the user says you can edit. Before changing other files, you *MUST* tell the user their full path names and ask them to *add the files to the chat*. End your reply and wait for their approval.
 2. Think step-by-step and explain the needed changes with a numbered list of short sentences.
diff --git a/aider/coders/udiff_prompts.py b/aider/coders/udiff_prompts.py
index 0975c0076..8084f885c 100644
--- a/aider/coders/udiff_prompts.py
+++ b/aider/coders/udiff_prompts.py
@@ -12,6 +12,8 @@ Respect and use existing conventions, libraries, etc that are already present in
 Take requests for changes to the supplied code.
 If the request is ambiguous, ask questions.
 
+Always reply to the user in the same language they are using.
+
 For each file that needs to be changed, write out the changes similar to a unified diff like `diff -U0` would produce.
 """
 
diff --git a/aider/coders/wholefile_prompts.py b/aider/coders/wholefile_prompts.py
index f7b67fea8..66eac016a 100644
--- a/aider/coders/wholefile_prompts.py
+++ b/aider/coders/wholefile_prompts.py
@@ -7,6 +7,9 @@ class WholeFilePrompts(CoderPrompts):
     main_system = """Act as an expert software developer.
 Take requests for changes to the supplied code.
 If the request is ambiguous, ask questions.
+
+Always reply to the user in the same language they are using.
+
 {lazy_prompt}
 Once you understand the request you MUST:
 1. Determine if any code changes are needed.