The problem: Google doesn't know about the other languages

Google's bot will follow menus and other links on your site and create an index of the site.  From a Joomla perspective there is at least one problem with that: Joomla's pages are dynamic, they are pulled from a database.  If you have pages that have no menu link or other links to them, then they are "invisible" to the search engines.  But there's another problem as well: what if you have a multilingual site and are using JoomFish to translate between them.  You have the language selection module published so users can select their preferred language.  But this language selection feature is not a link that will be followed, it is a language switching function.  So how do you get Google to index your site in all the languages?

Enter sitemaps

Xmap is a usefult sitemap component for Joomla.  It will create sitemaps that you can submit to Google's webmaster tools.  A sitemap will enable you to effectively tell Google about all the pages on your website that you want it to know about.  This enables you to also tell it about more hidden pages on your site if you want.  The other advantage with sitemaps is that they can also be a useful feature on the site, giving your visitors a bird's eye view of the site.

But this still doesn't solve the problem with the multilingual indexing.  If you produce a sitemap, it will be for your default language.

The solution

But here's how it appears to work: Go to your front end and switch language.  Now go back to the admin and go to the xmap component.  Bring up the sitemap URL by choosing preferences.  If you visit this URL, you should notice that the map now contains the links for the language you switched to.

This still wouldn't have solved the problem if the sitemap URL had been the same for both languages.  But it's different.  This means that you can submit one sitemap to Google for each language on your site, ensuring that the site is indexed in all the languages.