It's not abnormal, especially in boys, for language skills to be under-developed around 2 years old. Does he show promise in other areas like holding crayons, building bricks and digging the garden? Sometimes other skills whoosh along almost to the detriment of others like talking or even walking, but it all levels out in the end. Boys are particularly stubborn and like to do things in their own time.
The most important question to ask is does he make eye contact? Absence of looking at someone in the eye can indicate a problem. Try to see how he responds to different expressions.
Does he go to a playgroup or nursery? Very often their speech comes on in leaps and bounds when they are with their peers and once he starts school he may well make good progress.
It is worrying for you, but your family will know best whether he needs assessing. I would let things tick on a bit longer then start suggesting a check with a health visitor, preferably one who has seen many children over many years.