||Verb based on Proto-Celtic *lab(a)ro- 'eloquent, talkative'. Further cognates unclear. "These Celtic words may have been onomatopoetic in origin; the connection with ME flappen 'hit' suggested by IEW (831) is a mere possibility (if this is correct, the PCelt. form of the root was *flab-), cf. also Germ. labern 'babble'."