Why cats sometimes make baby cry sound?

Ha! My cat knows my voice and when she feels like it she will actually respond to it. I think they know their names and a whole lot of other stuff, they just choose to ignore you. My cat will walk by you and you can call her and call her, if she is in a mood she pretends you didn't even speak! It is so annoying sometimes, so when she jumps on the bed and meows to be scratched sometimes I ignore her as though she didn't even speak!! LOL She lays down and goes to sleep!