You covered all kinds of media but music, but Enya sings in a made-up language, but not exclusively. Just five songs are in Loxian, a language her songwriter made up for her after she did the song from Lord of the Rings (with some lyrics in Elvish or whatever the Tolkien language is). So she wanted a language that would suit her style and her songwriter made one for her.

The cool thing is, they wrote this whole sci-fi backstory for it about how the Irish go to space, to the moon, and they jump to a faraway galaxy. Also, Enya only sings the water dialect of Loxian — they have a dialect for each of the four natural elements.

The Enya songs in Loxian are:

• Less Than a Pearl
• The River Sings
• Water Shows the Hidden Heart
• The Forge of the Angels
• The Loxian Gate

The first three are on the album Amarantine; the last two are on Dark Sky Island. IMO Loxian Gate is the best of the lot, followed by The River Sings. If you listen on Apple Music or something that, you can watch the lyrics go by as she sings them, but it will not translate them. There are translations online, though.