Basically, the Dreamcast is only emulating games, even USA roms, in Japanese. Also, for some reason, the speed of emulation is double what it’s supposed to be and I couldn’t find any settings to stop this. Going through the menus is fine, but when cutscenes and gameplay start the game, sounds, and music double in speed.
I tried different roms in case they weren’t actually the US release, and I tried different BIOS, but none of them seemed to fix the issues.
I found a way to set the language manually. It looks like, by default, the display language is set to Japanese.
If you’re on controller, press A, B, X, Y and Start all at the same time.
If you’re on keyboard, these buttons are, by default: Z, X, C, V and Enter.
If it worked, you’ll get booted out of the game and into the Dreamcast’s main menu, which is in Japanese.
If all it did was just put you on the title screen, just try it again until you get booted out into the menu.
It should look something like this.