Hmm, being trilingual myself (Dutch, English and German), I'd say there are many benefits to this. Not in the least being able to understand other people when they think you can't
.
Other then that, my country being small and all, it's nice to be able to communicate with your neighbours and a significant part of the world in an economic sense of course.
I wouldn't know any disadvantage anyway. I'm hard pressed how knowing MORE is a bad thing.
I hunt for the truth