croak (v.)

early 14c., crouken, of birds (crow, raven, crane), "make a low, hoarse sound," imitative or related to Old English cracian (see crack (v.)). Of frogs, c. 1400. Meaning "forebode evil, complain, grumble" is from mid-15c., perhaps from the raven as a bird of foreboding. Slang meaning "to die" is first recorded 1812, from sound of death rattle. Related: Croaked; croaking.

"a low, hoarse, guttural sound," 1560s, from croak (v.).