So this is something I've been wondering about for a while. In Fantasy, Sci-Fi, and sometimes Horror, and whenever a story is not set in the real world, there tends to be fictional languages of some sort. Elvish, Klingon, Dothraki - the list goes on. But what about the use of languages like Latin, Greek, or Japanese? Whilst you would need to put in some logical reasoning behind the use of those languages in a world that is not Earth or does not involve humans, I'm still not sure whether using them would be 'pretentious' or not. For example, I'm using Latin as a language spoken by a 'ancestral' race of sorts, but I'm not sure how a reader, especially one who understands Latin fluently, will react to its use. What are your thoughts on this matter?