1. You can create aliases for tags, but this does not add localization to the tagging system. Tag aliases would just replace instances of one tag with another, so "生命" could be automatically replaced with "life", but you cannot currently make all three work as the same tag.
Implementing localization like this would require fairly significant work and is something I'd only be able to look into if there is enough of a demand for it, and it'd be implemented in an IPS 4.5 release of the application at the latest.
2. As there is no official way of localizing tags, there'd be no way to detect which is English, Spanish, and so on, so there's unfortunately no way to do this.
Hey Daniel!
I actually have implemented something sort of like this myself using the Pages application, with descriptions and links to search pages for common tags. You could probably do something similar with Pages if you have it.