As someone who has problems processing spoken language, I often used to have CC on all the time. Now I don't watch commercial TV, just Youtube etc., and let me tell you, there seems to be at least 2 kinds of CC. First, is computerized. Second, I know because my DIL does this, is someone typing live. The first is notoriously ... wrong, just wrong.  Oh, there's a third, of course, for old-fashioned TV, someone types out the CC after the fact, but before broadcast. Hope this helps. Can't speak to the missing "W".