When my son was preschool age, for whatever reason he HATED learning German (my mother's native language) and would actively resist when we had a German-speaking babysitter. We decided not to push it.
He would tolerate German kid song CDs, if I read him a German book, or a German-language movie/TV show, but he MUCH preferred English or even Spanish. Even though we are not a predominately Spanish-speaking household, Spanish is a much more common second language where I live so I suspect he felt more at ease with it. Fast forward to now, he's six and he VOLUNTARILY speaks German with his grandmother now and will initiate German conversation. What a turn-around!
So, my advice is to see what your kid likes, try not to be too overbearing about it and foster what he/she does like, and then expand as the kid gets older.