I don't really get all these conversions people are doing, given that the lingua translates such that it provides the best understanding for the listener, presumably it's already in earth years???
Yes and no, from my understanding. The Lingua does translate an approximation that would fit our (human) understanding of abstract conceptions (time), but I think they were trying to convert it to Wolven years? Which wouldn't work though, since it was never explained how many days are in a year on Adastra, only that there are 19 hours in a day, IIRC.