Bahasa means language. In some country, if you said 'I teach bahasa', that's mean 'I teach this country prime language'... and it could be any language!
first languages , hm... if by education from school . we learn both chinese and english together at the same time . so i speak both , but my family speak a multi of languages so i learn to speak hokkein , teochew and cantonese and a little malay when i was a kids . and since i stay in thailand for 10+ years now i speak more Thai then any languages i know