Hi,

I'm wondering if there's any standard way to put some additional info to tags. For example I would like to have a "language" tag, then I would also like to tag some of my files with keywords like "summer", "christmas" etc. This would be very useful to create dynamic playlists. Do you have any suggestions?

If you want to add a new field such as "Language", you are free to do so. You can add just about any field you like, assuming you're not relying solely on ID3v1 tags. As for keywords, you can choose to simply add them to the standard "Comment" field or create your own field (like "Keywords" or "Tags").

Rokkaz> Thanks, I knew I could create my own tags in ID3v2. I was wondering if there is any standard for such information. Probably isn't so I'll create my own. :-)

You can do that very easy with foobar2000.

As for "dynamic playlists" you might have a look at foobar2000's "autoplaylists" They are updating automatically based on filetags.