Most movies and some tv shows in the US now spit out an OST but most of the songs are actually pop/rock/country hits that already exist or are being released simultaneously with another album. Most anime music on the otherhand is created specifically for the work and may contain not a single cd, but dozens of them, most filled with songs that were never actually played on the show to begin with.
To give you an example, it would be like imagining say Star Trek the Next Generation coming out with all sorts of soundtracks containing not only the background music but also full blown songs with lyrics and sung by the characters. Many of these songs will never actually appear on the show at any point but every single major character would have his own 'character song', sung by the actor in question which epitomizes his character in some way. Worf's Michael Dorn might have a Klingon opera'esque piece where he sings about how his warrior's heart is torn between blood and duty while Will Riker's Johnathon Frakes might have a jazzy number where he sings about all the loves in his life. This doesn't even include all the 'audio dramas' which are also included in these soundtracks in which the various actors will perform as their characters in something like those old radio dramas in an era gone by.
It's pretty amazing when you think about it. What's really remarkable is that the Japanese snap up these offerings which I think is why it would never work in the US. I just can't see Americans being all that interested in all of these extras in most cases. You could probably get away with it with Harry Potter or some other franchise with die-hard fans, but I just can't see most people really being interested in buying cd's so they can listen to Rachel from Friends singing about Ross or Jack Bauer rapping about how he's going to kick some terrorist ass.
Wow, that was a major digression. I got pretty far afield from what I wanted to write about, namely that it's odd that I'm even interested in foreign language songs. Not having understandable lyrics takes away a lot from a song but there are some melodies that just click with you. It's more of a gut feeling sort of case since there's nothing you can really ponder or analyze about it. You just like some songs and don't like others.
I was recently thinking about an anime series I wanted years ago called Tiny Snow Fairy Sugar. It was one of those cutesy shows that pretty much automatically give you a mild case of diabetes. I always liked the opening song and I was amazed to discover that it's actually the Japanese version of a song by The Rubettes put out in the 70's. Here are the two versions, anime first followed by the original.
This got me thinking about whether the reverse ever happens. Japan puts out a ridiculous number of anime soundtracks and some of them have really fabulous melodies that would make for great songs in English. It seems like a shame that there isn't more cross-language sharing of music like this since I would argue that it must be easier to come up with good lyrics than a good melody. It almost seems like a waste it only gets used once and will likely never be well known outside of the country of origin due to the language barrier.