There are many recordings/works in them on the LotR soundtracks (and then some) and at least one (but probably more) tracklist in these languages – it would be nice to have them filed properly

A few examples:
http://musicbrainz.org/work/a57b331d-5ccd-4481-b0ac-f7559766d9be
http://musicbrainz.org/work/5173c407-3a42-4ec5-ac1e-d61ad526b197
http://musicbrainz.org/work/715ffeed-630b-48f4-a016-f0b4e5230cd3
http://musicbrainz.org/work/af89c72b-b792-40ce-81b0-9e16b8ba6a4d
http://musicbrainz.org/release/d8767b11-bae7-4ef4-8d78-c25fc83a543c