In a word, YES! He's picking up all sorts of things, the sound of language, the way the words/sentences fit together, the rhyme of the words (in books that rhyme), vowel/consonant sounds, stuff like that. Plus, by you holding the book correctly (when he's not trying to eat it LOL), he's learning how books work -- front to back, left to right, how the pages turn.
Also, you can always give him one book to eat and hold one for you to read.