R.R.
While it definitely is a phase you need to continue to tell him, "No hitting," or "We do not hit," remove him to timeout and take away the toy, otherwise he has no disincentive to stop hitting.
And you're right, his not being very verbal is a problem for him, encourage him to use his words, to express "I want this" or whatever it is. In a few months his spoken vocabulary will more than likely explode and he'll be better able to make his wants and needs known and hopefully will have less of a desire to hit. Until then just be consistent so he knows what you expect.