They're not random. She has two different voice clips, both in English and Japanese. -One plays if she's fighting enemies at or above party strength. -One plays if she's fighting enemies much weaker than the party (where she just doesn't care.)

She's not saying random phrases, but the English names of the skills are definitely not direct translations of the words she is saying. I can recognize her saying "kaiten" which generally means "rotation" or "rotating." This may be the name of the arte she is executing. In another phrase I think she uses the word or phrase for time, or "out of time" -> "jikan" and it's kind of common in fighting/anime content to hear it for a character down talking their opponent like they have better things to do, or they have to move on. So it's not that she's saying random phrases. Her voice during her artes are not her saying the name of it like 98% of all Tales of characters. She's essentially talking to her opponent, or maybe in general, about what's going on while executing the arte. When I read the other comment by Robbie, I think it's pretty interesting mechanic if she says different things if the opponent is stronger versus weaker than the party. Having different chat for this usually happens in the post-battle victory banter between the party members rather than arte execution. It lines up with me roughly translating that she's saying she's out of time or in a hurry.

I disagree, in 2022

@@glutamate5886 you've got it backwards