“In Persona 4, he is generally a silent protagonist, as in the series tradition. Except for instances where he audibly speaks when summoning a Persona and so on, with his personality ultimately based on the player's actions and decisions. This is emphasized in Persona 4 Golden, as the Investigation Team Members comment on how he doesn't talk much when equipped with the Butler Suit."

"The general personality that may be picked up from his behavior is that although he's calm and neutral, he's outgoing and caring towards his friends, and he has a freedom of a sense of humor along with occasional flirtatious or silly behavior.”

Voice Example

https://youtu.be/6vcxeCVyLVI?si=0SSGJlUlM_cVg9rw