Tripitaka headcanon because I feel like projecting.
He has two voices: a lower one for when he's comfortable and a slightly higher one for when he's around new people or someone who makes him uncomfortable.
He has no idea that he switches voices, but his disciples caught on pretty quickly and know exactly when he is and is not comfortable in a situation.
It took him a couple days after taking on each new disciple before his voice lowered back to normal. Royalty will never hear his normal voice, and deities only hear it when he doesn't know they're there.
His disciples have used this before to protect him, such as the time he was speaking normally one day with a fellow monk, and the next day, the pitch rose again. Turns out, they'd threatened him.
He uses the higher voice around Faming.
