Indian local board allows English which I can speak, this I don't think justifies me to be able to join conversations in that local board, I apply that rule to all other local boards.
I dont think you have to be so strict about it. Whether jumping into a discussions depends a lot on what folks are talking about. If you are clueless about the topic and got nothing useful to add, better to just read instead of barging in, no matter what board its happening on. But say someone asks a technical question or starts a discussion that interests you - then you can chime in if you want even if it is the Nigerian or Indian board. I mean if its in English and all and, as long as you are constructive and not wasting peoples time.