I had trouble with the "You can't read without subvocalization." part too.
I can't understand if by subvocalization he means moving your throat/mouth or simply repeating the words you are reading in your mind without moving any muscles.
Wikipedia says "subvocalization is defined as the internal speech made when reading a word"[1], which further confuses me.
I don't move any muscles while reading, but my internal monologue repeats the words I read, does this mean i subvocalize?