Languages doesn't seem to be working.

A couple of things are going on that I can't figure out. First, I installed the Languages for WordPress. It seems to have installed fine, and the menu is in the settings area. But when I change the language, nothing happens. I experimented just to see what would happen.... nothing.
Also, the Select Language at Signup feature for this plugin doesn't seem to be working. I set up a bogus account after Network activating it, but never saw a language option. You can check it out at allaboutchile.com.
I'm using the Dynamix theme. Could that have something to do with it?

Thanks
Joe