[In form a deriv. of QUACK v.2, but found earlier.] intr. To quack, as a duck. Hence Quackling vbl. sb. and ppl. a.

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1564–78.  Bullein, Dial. agst. Pest. (1888), 64. Vpon a tyme when quacklyng Duckes did speake and caklyng hennes could talke.

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1825.  Hone, Every-day Bk., I. 534. The loud … quackling of ducks … is a sign of rain.

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1837.  Carlyle, Fr. Rev., II. I. i. Simple ducks … quackle for crumbs from young royal fingers.

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1865.  Mrs. Whitney, Gayworthys, I. 11. Underneath … splashed and quackled the ducks.

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