I personally don't have stuttering and hence can't really feel you, but I know of a guy, Finnish fellow, to whom I once asked about his preferrence of English over his mother tongue for streaming. He claims that switching to English makes him stutter less or not that seriously and therefore he'd rather stick to it. Like I said, I don't stutter myself and can't really tell whether picking up a new language will work out the same way for everyone as far as stutters are concerned, but I guess giving it a whirl is better than nothing.