[asyx]

Rule of thumb in Germany is that everything code related must be in English for the simple reason that should you hire people that are not speaking German, they will have a much harder type getting into the codebase.

And that's for projects started in German companies for German users written by German.

The idea of contributing to an open source project that hasn't a single German sentence anywhere to be found and then adding German commit messages seems insane to me. I'd never even thought about this.

So yeah. Just tell him / her to rewrite the commit messages in English.