My cousin is already 3 1/2 years old but still can't pronounce a complete word. Should his parents bring him to the doctor already?

i have a cousin also, can't pronounce a word in a sentence, what i observed about him, he's not sociable because of watching cartoons .at first I don't understand what he's saying and then I noticed his language is english and our dialect is Ilocano. so there we understand now.