I find children speak when they are ready my granddaughter is saying a lot of words she is only 21 months she gets on the phone and tells me a story i only understand about 5 words and my daughter tells me what she is saying.My other granddaughter who will be 4 next february does not speak to me at all.she is a very quiet child she speaks to her other grandmother in the language she was taught which was Samoan.My son married a Samoan girl and they have been trying to tell my granddaughtetr to speak  english.So i think most children will talk when they are ready if they attend some sort of child care or pre school they might talk faster.But i have a great time talking my granddaughter on the phone  and trying to understand she is such a chatterbox.

Comprehension is the main thing. As long as he understands two and three step instructions then there isnt really a problem. All kids talk at different rates, like everything else really and statistically boys talk later then girls. My eldest didnt start really saying anything bar Mumma, Daddy and duck, until she was 20 mths old and then by 2 was talking in sentences. Unlike DD2 who babbles away with lots of words at 19 mths. I wouldnt be worrying. Just enjoy the peace while it lasts :)

I have a 21mo who only says about 6 words anyone canunedrstand, but ask him to do something and he knows exactly what you are asking him to do. Apparently my Dad was nearly 4 when he started talking and consequently hasn't stopped for the last 60 years to make up for it *LOL* I think there's a wide range under the umbrella of "normal"