An Etymological Dictionary of the German Language/Annotated/prahlen

by Friedrich Kluge

prahlen, verb, ‘to parade, vaunt, boast,’ from Middle High German prâlen, ‘to make a noisy parade, shout’; compare the equivalent Dutch brallen and pralen, as well as English to brawl. Its connection with French brailer, ‘to bawl,’ and Welsh bragal, ‘to brag, bawl,’ is uncertain.