@darius I think also the community around the programming language is super important. e.g.
- Can women participate without fear of harassment (if there is not currently some semblance of gender balance in the community and its organisers then the answer will be no)
- Is it acceptable for community members to make beginners feel stupid / give non-answers telling them to search google etc
- Are racists/nazis tolerated
etc
It's pretty rare for a programming language community to not fail at all these tests..