Maya is an Indian concept that is similar to delusion. Hindu concepts are concerned with how the Maya mind tricks the individual into not seeing the real. Then, Hindus and Buddhists practice meditation to bypass Maya and RESTORE one’s real self.
Vocalposture is comparable here–it’s saying that the Maya mind tricks the individual into not hearing his real voice. Straightening the posture (comparable to meditation’s focus on straightening the spine) is also used to bypass the Maya hearing.