This would be great if you wanted to talk to yourself without anyone understanding what you’re saying, for example, or if you didn’t want anybody to know what you were writing down. It might also be useful if you enjoy lots of foreign language media (see music, tv shows, movies) and want to experience the “original” rather than through dubs and subs.
Personally, I would go for either Russian or Estonian, both of which are because I frequently listen to lots of music that are in those languages, and they aren’t spoken by any of my friends.
Japanese, for the media. But really…
Loxian. The language was created by Enya’s songwriter, Roma Ryan, and the two of them are the only users of Loxian. Ryan’s husband Nicky (Enya’s producer) passed way last year, and his wife is probably not far behind. She’s in her 80s (Enya is in her mid-60s herself).
It is a real language and it exists in exactly five songs by Enya. The best one IMO being The Loxian Gate. The only reason we have translations is because Roma herself has written them, and we have to take her at her word that they are accurate, because it’s her language.
If you don’t want to look up any songs and hear it, it sounds like Gaelic (traditional Irish language) with some Elvish (like from Lord of the Rings, which Enya did the song May it Be from, and sang part of it in Elvish) mixed in.