I realize the universal translator is just a hand-wave to avoid the "Aliens Speaking English" trope, but there are at least some basic rules established for it:
When it translates, it will use the closest approximation in the database, it can learn as it hears more of a new language, it's apparently a neural implant (at least with Ferengi), and probably a few more that I'm missing.
Does it keep the original speaker's voice, tone, inflection, and in this case, melody? Does Kira hear Vic singing in perfect Bajoran or is the universal translator belting out Frank Sinatra in Lwaxana's voice? Do the lyrics still make sense with the computer translation?
I very rarely complain about the UT, and I enjoy the Vic Fontaine component, but I just have a hard time combing the two lol.
Sometimes I wish they would have gone with a "standard" language like Space Esperanto that just sounds to the audience like English rather than the UT.
Update: I completely forgot Federation Standard existed, and that's probably the language Vic is using, and Kira is very likely fluent due to her time spent on DS9. It's kind of a retcon since that wasn't mentioned until DIS, but I can live with it.
Did someone say Space Esperanto?