Translation module: how to "force" a language

Hi - I have the basics of the language translation utility/module working, what I'm having trouble with is the concept of getting it to respond to a specific language using a specific URL structure (or something else). Since all the URLs are the same regardless of the language, I am stuck trying to get it to default to a language other than the default. 2 languages working: EN and FR. The default one is EN. How do I link to the site (from another location) and ensure the site responds in FR and not EN by default?

Thanks.