My daughter is just over a year and a half old. Although she certainly understands many of the words we speak to her -- banana, cheese, water, outside, shoes, cup, yes, no, the names of certain people -- she does not ever speak very many words back to us.
Instead, she prefers to make soft, sweet little noises. Sort of a mix between humming and singing.
hum (verb) - make a low, steady continuous sound like that of a bee
I love listening to these little noises she makes. It will not be much longer before she starts speaking many words and then full sentences. She will soon learn how to yell, scream, demand, and talk back. But for now, even when she is demanding something or trying to refuse and tell us "no", it comes out in mostly soft hums and sweet noises. It is music to my mama ears.