Are Wii games multilanguage (EU Region)

You might try first looking to see if there are composed albums of the sound track. You'll be endorsing the availability of the music separate from the game (many already are sold as MP3s, but a CD is still easier to rip than extracting from a game) which hopefully will entice publishers to make the sound tracks for other games available for sale as well.

examples:
Super Mario Galaxy 1 & 2
A Boy and His Blob (to be released "soon")

I believe the reason is technical in nature. The Wii has a very limited amount of disk space. I don't think there is enough room for storing demos, especially for downloadable games.

In recent system updates, Nintendo has created the ability to play games from an external SD card. Maybe there will be more demos as a result.

Limited disk space was also an issue with the Xbox, yet there appear to have been many demos available on that platform. Maybe, then, it is also just a cultural issue: the Wii ecosystem just isn't a place where demos are common. This can be frustrating. I once downloaded a Metroid: Prime Corruption "demo" only to find out it was a game trailer.