An Etymological Dictionary of the German Language/Annotated/krabbeln
krabbeln, verb, ‘to crawl,’ with Low German permutation, in contrast to Middle High German krappeln, of which the variant krabelen occurs, whence also earlier Modern High German krabeln. The form with a double labial may be due to its being popularly connected with Krabbe (Krappe), for in Scandinavian also a simple form is found without this double labial, Scandinavian krafla, ‘to scratch with the nails,’ and krafsa, ‘to shuffle with the feet.’ English grabble, grapple, grab are connected with Low German and Dutch grabbeln.