My teenage DSD does it, even though I didn't know there was a name for it. She pairs that with trailing off into words that don't mean anything ("whatever, whatever, blah, blah, blah.....") and so you are left trying to decipher whether she actually MEANS anything by her communication, and, if so, WHAT she might mean. Her dad is really good at making her define her reference points so we can tell if her brain is working or not.

Hehehe.......gravelly, growly, whatever whatever.....