"Chibble" was first used by me in an email to a friend of mind in 2008. I described an example of how my dog Peach understood English. I had watched her chew herself when she got an itch, which I assumed was a flea because her mouth moved around in a path, rather than staying in one place, as if she were following something. The articulation of her teeth and lips were notable because her lips were curled back to allow closer contact between her teeth and skin. This exposed her gums. Her lower jaw jutted out so that her top and bottom teeth were aligned. She chattered her teeth in tiny ,rapid, precise motions, just opened enough to mash a tiny flea. One day I held out my arm to Peach and asked her, "Peach, get the fleas off me." She instantly began chibbling up and down my arm, delicate as could be, just above my skin, without even pulling one hair. She never found any fleas on me, but was always willing to check, if I asked her. The precise delicacy of the motion sets "chibble" apart from "chew" and "nibble", I think.