LogFAQs > #913205093

Yeah, for written dialogue, you have the limited time Forging Bonds mode which is just 4 specific characters regardless of whether you have them or not, you have getting 5-star characters to level 40, and then I guess story/paralogues/xenologues (which you're not going to find anything great in).

Most of the voice acting for a character can be heard by tapping on them when you're on their character screen, but they also have a few voiced lines for attacks when their special activates and for when you move them around in battle. There's a place in the game where you can view that stuff for all characters you summoned in the game without having to actually battle somewhere in the menus, but not sure where that even can be found in the menus at this point.