I’ve noticed some non-Asians really get annoyed when they hear people speaking other languages in public. They make that annoyed look, and you can tell they are thinking ‘foreigner go home’! I think for some reason they get self-conscious and think that perhaps they are being talked about, and it makes them insecure. Funny thing is, oftentimes they are being talked about! :) It’s no secret that foreigners use their mother tongue when they don’t want to be understood by the gwai lo.
Personally, I don’t mind it. I have friends who are Korean, and sometimes I go to get togethers and they switch to Korean. I don’t know what they’re talking about but I don’t mind. (I’m guessing they are talking about how good looking and well-hung I am…) Sometimes, I’m sure it just feels better to say certain things in Korean. I just sit there, and listen to the beautiful, glottal sounds.
But, in general, I personally try to speak in the language that is most common amongst all the people at the get together. So, even if there is only one person who doesn’t speak Japanese out of 10, just to keep them feeling comfortable, I will speak English the whole time. Just my own policy for group harmony. It’s just considerate. Nobody likes to be left out.