This is interesting, I've thought of this before.
I write comments and commit messages in English, mainly because programming is collaborative. I am a member of a local association of young programmers, and in the community (discord, meetups) we speak Finnish, however all interactions on github are in English, so are function and variable names, as well as comments. If someone makes a PR and it's reviewed, it happens in English, even if both parties are native Finns.