You can say: I don't speak English well. I do speak some English. I try, please speak slowly. My English is not very good. My English is poor. Have you seen the "Do you speak English?" video? http://www.youtube.com/watch?v=rxUm-2x-2dM

You can just say 'little' and that should do the trick. Although i like how the typical responce to that would be for the Englishman to just repeat himself more loudly hehe.

you can say" I can ,but a little"

hi,Anderson I have been asked this questions many times,and my anwser is " yes, I can speak a little." or " yes, just a little." or " yes, but my English is poor." Good luck!