His manner of speech in Loving

If I've seen him in anything besides Loving I don't remember him, so I have a question about the way he talks in Loving. I understand that he's an Australian who is acting with an American accent, and as a native of the Southern USA I think he does a decent job. But I'm trying to figure out if he always sounds like he has mush or tobacco in his mouth when he talks. Heath Ledger, another Australian, did the same thing in Brokeback Mountain, and I found it a little irritating. Is that his usual way of talking, or did he seem to think that's the way southern men talk?