My DS had a profound speech delay. I don't think he was saying anything at that age either. I'd probably hang in therefore another couple of months and see if there is any change. If not then get his hearing tested. From memory we needed a GP referral but I could be wrong.
I didn't start speech therapy with DS until he was about 3 years 2 months. I wish we had started sooner but I thought it might just improve by itself. 3 years later and with heaps and heaps of speech therapy he is much improved but still about 18 months behind everyone else his age.