to chirp, warble, twitter; or, to speak loudly (see Molina)
Alonso de Molina:
chachachalaca. ni. (pret. onichachachalacac.) gorgear o hablar alto. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 18v. col. 2. Thanks to Joe Campbell for providing the transcription.