Mitzi does something like that - I call it her "meep." She also mrrps and, of course, meows. I think Mishi has been giving Mitzi singing lessons whilst I'm at work as she is now talking and singing a lot more than she used to. It's so cute, although my favorite are her little "silent" meows. I know she's probably making a sound, but my human ears can't hear it; I just see her little mouth moving. No distress signals, just meowing to let me know she's here and wants pets. She's watched it work for Mishi long enough so I guess she figured she'll try it too .... it works!

Mishi talks and sings all the time. Some of my favorites are his "umgawa" sounds, usually when he wants food.