An Etymological Dictionary of the German Language/Annotated/lachen

by Friedrich Kluge

lachen, verb, ‘to laugh,’ from the equivalent Middle High German lachen, Old High German lahhên, lahhan, earlier hlahhan; the hk of the High German is due, according to Gothic hlahjan (preterite hlôh), ‘to laugh,’ to an older hj, Anglo-Saxon hlyhhan, English to laugh, and the equivalent Dutch lachen. In the non-Teutonic languages the stem hlah, pre-Teutonic klak (probably onomatopoetic, like the cognates of klingen or Lithuanian klegĕti, ‘to be noisy, laugh loudly’), is not positively authenticated. — Derivative Lache, feminine, ‘laugh,’ from Middle High German lache, feminine, ‘laughing,’ compare English laughter, Anglo-Saxon hleahtor, Middle High German lahter, ‘laughter.’ Lächeln, verb ‘to smile,’ from Middle High German lęcheln, is a frequentative of lachen.