That depends on a few factors. First your boss is foreigner so English is the most used for communication.In this case it is a necessity.
Second if you plan to study abroad then you should be able to speak English regardless which country you go.
Actually, there are a lot of advantages if one can speak foreign language, not strictly English, being Chinese, Japanese, Korean french etc. It does no harm to you to be able to express yourself in other languages other than your mother tongue.