I'm not even very good at my own language. I used to have a better vocabulary, but as I started learning more and more engineering, I started forgetting more and more words and spellings. My head's all full of numbers now. Also, I took French for three years, but I don't remember a word, and the only thing I know in German is "My name hurts."
I'd love to learn another language, but I'm not very patient. I'd have to work up a really strong urge to put some time into it, but I have to admit that being monolingual sucks.