Synonyms for Sing (same or very similar meaning)
WordNet sense 1 (make a whining, ringing, or whistling sound):
whistleWordNet sense 2 (divulge confidential information or secrets):
babble, blab, peach, talk, tattle, spill the beans, babble out, blab out, let the cat out of the bagFrom the ODE community, based on WordNetadd/edit