It is more common, I think, for Scandinavian language ballads to reach higher levels of popularity through their modern recordings. For example, the Swedish folk rock band Garmarna record a lot of trad ballads in their style. Their album Guds Spelemän (from the 1990s) was very popular, and became very influential, especially among the harder rock and metal scene. So since then the traditional Swedish ballad Herr Mannelig has been covered a fair bit by such bands.

Folk metal is perhaps pretty niche, but it is more youth orientated at least, and maybe less niche in some parts of the world. Several bands that have recorded Herr Mannelig (in Swedish) are not from Scandinavia at all, but from Germany and eastern Europe.

Video with a live performance
(in Swedish) by the German band In Extremo. There are obviously a lot of people there ....

Anyway, that's just an example.