An Etymological Dictionary of the German Language/schnattern

by Friedrich Kluge

schnattern, vb., ‘cackle, gabble, chatter,’ from MidHG. snateren, ‘to cackle, croak (of frogs), clatter (of storks), chatter’; comp. Du. snater, ‘beak,’ snateren, ‘to chatter, boast.’ The stem is not found elsewhere.