First thing to ask is - is his hearing OK? This can be a major factor in speech development. Does he 'babble' at all? Did he ever? Or does he just use the 2 words he knows at the right time? Can he miaouw like a cat, woof like a dog, make car noises...? What are his two words? (I'm put in mind of the non-communicative teenager sketch who only knows 'money' and 'wallet' but that is unlikely here!! sorry)
Do you make him ask for drinks, biscuits etc or just offer as appropriate because you 'know' what he wants?
If he makes noises and can hear, it may be he feels no need to talk - he may just be late or even lazy! If in doubt have a word with your GP or HV
Agree - go to your GP. Could be he's a late developer, but at the very least his hearing needs to be checked out (even if he can hear quite a lot it is possible to be missing part of the hearing range which would affect speech).
Does he understand what you say to him? How does he communicate what he wants to you?
of course he MAY just be a late developer, but I personally would be concerned if, at nearly 3, a child was only saying 2 words.
I would see the HV. we had concerns about ds2 and his lack of speech and at 2.5 I saw the GP who told me she doesn't refer and that I need to see the HV. that was crap, but tbh the Health Visitors DO normally do these kind of referrals and should have all the paperwork readily available and IME it was far easier going through them.
They will probably ask you lots of questions to try and establish whether it's a potential hearing/speech issue, or whether there is some other underlying problem then they will refer you for hearing tests, speech and language therapy and anything else they feel appropriate
waiting lists are often long for these things, so it's best you do this ASAP. If in the meantime he starts talking then all well and good, you haven't lost out at all and you can just cancel the appointments if you need to. but better to be in the system just in case