FAQ: How many languages does SQL Server 2005 ship in?

This is an interesting one, I couldn't find this in the product docs, although I am sure it is there somewhere, I could look at the SKU spreadsheet to decipher the SKU codes, however Alan Brewer from the UE team had a better solution;

You can see the list here. Look at the Full Download drop down in the upper right of the page.

Note that Express Edition(however NOT Express Advanced) is also available in Portuguese (Brazilian), Swedish, and Dutch.