Lex78

I've been wondering what some of the speech language or voice disorders are that require the least vowel or accent correction as part of their treatments. I'm a non native speaker of English (and a new student of SLP) and, although I'm highly proficient (native-like), I still have a slight accent in some of my vowels and in my /r/. I'm thinking of taking some accent reduction classes, but still, I'd also like to know what disorders require the least or no sound examples to be produced by the therapist. Thank you!