To change the default language for new users on your site:

1. Log in as Admin.
2. Turn on Admin mode.
3. Select Users from the Admin Bar.
4. Edit the Visitor user.
5. Flip over to the Profile tab
6. Scroll down and select your preferred language from the Language pulldown.
7. Hit Save to save your changes.

To change the language for ALL existing users on your site:

1. Become an Admin
2. Go into Admin mode
3. Go to User Profiling
4. Scroll down until you find Preferences -> Language
5. Click Edit
6. In the Default Value(s) box, change English to the name of your preferred language.  Be sure to leave the quotes around the name of the language!
7. All new users who sign up to your site will have the new language as their default.

However, even with the above changes done, the first Setup-Screen will be in English. To change this to another language than English (e.g. German), you'll have to change the sql-sources to change the preferences, before a session is initiated:

1. Edit create.sql
2. Changes (with vi):
   %s/'English'/'German'/
   %s/'English\\'/'German\\'/