I feel the same way in the second language I speak sometimes. I can't imagine comfortably participating on the equivalent of HN in that language. So good going, at least you are asking this question.
I think a simple framework for this could be: Beginning, middle, end...
In the beginning I'd address HN. About half the community seems to respond less negative-emotionally if they are addressed in a friendly way up front, as if they are a contributor to a community. "Hey everyone in the HN community, thanks for being here, I am really learning a lot from HN."
Middle, "Asking in case anybody knows: What's a good new-ish underdog programming language with really good docs that have clear examples? I'd like to expand my horizons a bit and would appreciate any names you can share."
At the end, IMO it clearly helps to say, "English is not my first language, thanks for your patience".
This should cover your informational and social norms, which can cause issues if they are non-existent or if the post is too informational.
You will be misunderstood, but even more than that you will be scrutinized. People who are very logical often like to ask questions about others' questions. So I think you should just expect people to ask you to clarify, even though your English is probably fine. Hope that makes sense.
Good luck, good q, and I'm sure you'll do fine.