What do you think of Asians who are always gathering and using their mother tongue to communicate?
In addition to Paul ‘s answer I will say that hanging with other nationals of your country and discuss in your mother tongue while abroad is just a natural thing. In years living in China, I have seen many groups of Americans and none of them was using Chinese to communicate.
When you actually live abroad it just feels good to be with people that share the same culture and language as yours sometimes, because the experience of entering a completely different culture can really be overwhelming.
About making friends with them, what about asking them about their language? learning a few words? talk with them about their culture? Show some basic interest in who people are may be a good option to become friends with them.
Also maybe to enter a group of people while they are having a discussion is not the best way to meet them. Try to talk to them separately - they may even speak English.
This text was originally published in quora.