canadian immigration: language skill

Hi,

I got my Master in a U.S. university and have been working more than 1 year in a NYC based firm. All my colleagues are Americans.

I am considering applying for a canadian green card as backup. I don't want to
take a language test just for the application. My question is that if I claim
high proficiency in speaking, listening, reading, writing, do I have a very good chance to get approval?

Thanks in advance