New words in a foreign language

I have noticed that often in international group when people run out of topics to talk to they start ask other person to teach them their language or saying words and phrases in the other persons language . So far I have not liked much this topic because it is usually teaching bad words and basic "how are you" and so on. I feel like learning few phrases is not very useful but it is always nice to show a foreign person that you can speak their language and he/she will be probably impressed that you can say something. I wondered would it possible to take even more out of these little language learning sessions and learn little by little having a conversation in a new language.