yack (v.)youdaoicibaDictYouDict[yack 词源字典]
also yak, "to talk, to chatter," 1950, slang, probably short for yackety-yacking "talk" (1947), probably echoic (compare Australian slang yacker "talk, conversation," 1882). Related: Yacked; yacking. [yack etymology, yack origin, 英语词源]