Abhivaan is almost 1 and a half year old but does not say a single word . why?

A. Son first check is your child understanding every thing as per the age responding to every thing well enough to child doing all these things then speech is not a problem the child and pick up onto speech by the age of 2-2 1/2 years as well just need to interact more and more with your child and if you giving any screen time you have to completely shut it out