diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 35528fd..4f793ae 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -4,6 +4,10 @@ Thank you for your interest in contributing! `eve-mcp` is an MCP server
 that exposes the EVE (Earth Virtual Expert) API as a set of MCP tools.
 See the [README](README.md) for what the project does and how to use it.
 
+## Language
+
+All commit messages, code, and comments must be in English. 
+
 ## Development setup
 
 Clone with submodules and install with Poetry: