Space Esperanto
That could be the case here. Vic may be singing in Federation Standard (aka English) and Kira /Odo have learned it after hanging out with the Federation for the last six to seven years. Considering their backgrounds as people who lived in multi-lingual societies (from the Occupation), it wouldn't be the strangest thing for them to pick up a new language with some off screen effort over the years.
No worries. I think you have a valid point and it could also be a weird UT thing going on where Vic's words are translated idiomatically and not literally.