I'd say there is a difference and the second phrase is right. Its a statement, so its saying he doesn't know any foreign language, except English - so its an exception to the statement. The first phrase is making the statement that he doesn't know any foreign langauges, but then it contradicts that by saying - other than English, so therefore he does. I hope this makes sense, I could be wrong, but I was told that by an English teacher when I was at school. Hope it helps! :)