from The Century Dictionary.
- To bark like an angry dog; yelp; hence, to talk pertly.
Sorry, no etymologies found.
"Whup! whup! whup! yaff! yaff!" said Dick, as they came up to a field containing a flock of sheep, heavy with their long wool; and over the hedge he went headlong amongst them, making the poor timid, stupid creatures run as fast as their legs would carry them, with their heavy fleeces touzling and shaking about till each sheep looked like a magnified thrum mop being shaken to get rid of the water.