Making a theme multilingual by adding a custom taxonomy to posts and pages called “Languages”?

Recently, I’ve been thinking of implementing an easy and simple localization feature in my
WordPress site.

I thought about adding a custom taxonomy to my posts, and pages called “Languages.”

So when you click the link of the language it just filters the posts with that Language term.

I’ve been using WPML and it is awesome, but I just wanted an embedded implementation for my theme.

Have anyone tried this before?

What could be the pros and downsides of doing this?

The Pro: You can reuse native WP code.

Contra: You have to write your own taxonomy selector to avoid posts tagged with more than one language. The plugin Posts 2 Posts from @scribu should guide you to a more flexible approach.