I'm in the process of localizing a website. I was going to go the way of setting a cookie to the preferred language, and then display the respective language. And, if no cookie was set it would use the preferred language header, as set by the user's browser - and if the header was not set then it would default to English.
So - how does Google's bot work? Will it crawl all websites once each with a different language set in the headers so that it can get each version of the website, or does it even set headers? If not, then do I have to restructure all this so as to use a URL based language selector (www.domain.com/en/page.html www.domain.com/fr/page.html).