@OmSigDAVID,
The ability to speak various from child to child.
A normal 1 year old can only speak in one word sentences. "Mamma" In this case you look at your child and see point at the banana.
A 2 year old in two word sentences "Mamma, banana"
A 3 year old in three word sentences "Mamma, want banana"
A 4 year old in four word sentences "Mamma, I want a banana"
They still can understand more than they can say, but still it is limited to their little world.