As much as I sympathize with you, you can't blame your speech for everything. You have to be the person who really wants that job and you can get any job you bloody well want. Just work hard for it, you don't just get jobs just like that. They take effort and under the disability and equality act they cannot refuse you because of a speech impediment. Don't mention it on CVs and don't draw attention to it, it just makes it seem like you're pandering for sympathy. And they won't give you a sympathy acceptance. Work past it.