International students in campus

I have not spoken English very much since I came home from New Zealand and I am very concerned that I could have much less opportunities to practice English speaking than the last month. This situation will continue for at least for 4 years (until I graduate from university in Tokyo).

So I have been looking for someone to help me with the problem and in fact I became a member of lang-8. But this cannot stop me to speak, listen, read and write more in Japanese and less in the foreign language. It is inevitable as long as I live in the Japanese society.
Fortunately, my university has a great number of international student and I saw a few groups of Asian student today. I guess they were Malaysian or Indonesian.

Thus the question here is whether or not I could start conversation with them in English in a situation like that they have lunch in cafeteria. Could it frighten them? I long for advices from international students living in Japan. From my experience, I was very happy when other kiwi (New Zealander) student talked to me in Japanese.

Thanks.