Same word as yakketyyakked:

babble, betray, blather, blurt out, chatter, disclose, divulge, gab, gabble, give away, go on, jabber, let out, let slip, mouth, peach, prattle, reveal, run off at the mouth, run on, shoot the breeze, spill the beans, spill, squeal, talk through one's hat, tattle, tell, tell on, yak, yakkety-yak