The story
- Proto-Germanic · inherited from*klakōną“to clap, chirp”
- Old English · inherited from*clacian“to slap, clap, clack”
- Middle English · inherited fromclacken
- English todayclack
From Middle English clacken, clakken, claken, from Old English *clacian (“to slap, clap, clack”), from Proto-Germanic *klakōną (“to clap, chirp”). Cognate with Scots clake, claik (“to utter cries", also "to bedaub, sully with a sticky substance”), Dutch klakken (“to clack, crack”), Low German klakken (“to slap on, daub”), Norwegian klakke (“to clack, strike, knock”), Icelandic klaka (“to twitter, chatter, wrangle, dispute”).
Etymology from Wiktionary, CC BY-SA 4.0.