Likely. I can't find it now, but there was an HN story not long ago where someone used fairly rudimentary techniques to identify former/alt HN accounts based on stylometric similarity. It worked VERY well.

If I were going to post from a throwaway account for some reason, I would probably launder it through an intermediate language on Google Translate for one or two cycles. Otherwise, if I didn't bother with that, I'd certainly scatter some intentional errors here and there that I don't usually make.