Whats the sound that cats make with their mouth closed?

Question

Whats the sound called that cats make with their mouths closed that sounds like they are questioning something, like a HMMMMM??? sound.... lol idk how to explain it

Answer 1

As someone else said, it's chirping and it's cute. My cat does it when she wants something or is curious. As you say, it's like they're questioning something!

Answer 2

Purring

Answer 3

It's called a trill or chirp.  

Answer 4

My cats do that when they want something. To me, it's a parrot-like sound, right? I don't know how you actually call it though...