oh yeah, said by someone who wants something (see Molina)
Alonso de Molina:
yetla. o si, del que desea algo. interjection. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 36r. col. 1. Thanks to Joe Campbell for providing the transcription.