I just started playing these games a couple days ago. I'm on episode three, and I've just started encountering this weird problem where all the characters start speaking in slow motion.
It first happened when I talked to Coach Z for the first time. I restarted the game, and everything was fine. So I shrugged and thought nothing of it. It just happened to me twice, though, when I tried putting the record on the turntable at Pom Pom's club. It seems to be some kind of glitch triggered by a certain sound effect. This never happened in episode one or two.