Question for multi-language sites

How do crawlers handle the same URL present content in different languages?

[NetRoll]

I am wondering how do spiders are handling a site that displays different language content on the same URL?

We have a site that uses a cookie, but it could be profiling or even the browser's language, to determine the user's language and display the content in the proper language.

Should we modify the site so the language is passed in parameter in order to differentiate the different languages to make sure the crawler will scan all the pages?

Thanks.

[NetRoll]

Grrr... cannot edit the title...

You all understood I mean "multi-language"