Does anyone know what movie this is?

Its about this girl who is looking for another member for the debate team and she picks this guy with a lisp and he trys really hard but in the end she was just trying to make her team lose. and at the beginning the girls first partner that was really good realized something and just walked out and the girl was crying in the bathroom. another part the guy with the lisp throws like a cello or something in the girls window because hes hurt. please help! (: