If you want to communicate bwtter with him, maybe try starting baby signs, and saying the words for things he wants and having him repeat. For example: "Grunt( points at milk)" "Oh, you want some MILK? ( sign it as you say it) Can you say MILK?" If he signs or says milk, give it to him...try a couple times, for each item. We did this with my daughter and she was talking in sentences ( three words) by 1 year old, we started signing at 6 months.
I think signing opens up the same communication/speech pathways in the brian as spoken words, and I feel it helped my daughter to speak sooner, and better.
I would say, every time he asks for something have him repeat the word after you, and whenever you encounter a new item have him repeat it too.
Like others said it will come in time, but if you want to give hima little "push" that is what I would suggest!
Jess