I'm rather new to all this and was wondering about a few pronunciations myself, personally, I say Tune-ARE-ee (Tunare), and since Luclin is the goddess of shadows, I always thought that LUSS-lin sounded better in my head than either LUCK-lin or LOOSE-lin, but as the point has been made countless times, its varying pronunciations of imaginary words for the most part, and left up to whoever is saying it. For instance, my current main is named Preyforme, which is pronounced to me as PREY-for-me and not PREY-form as some people seem to think it is.
Oh well, these are the main reasons I hardly ever use teamspeak, since the printed word cannot in any circumstances be misconstrued.