It will take a lot more screen space as a dropdown than as a tab. Also people will expect that the language of the settings will change immediately, which is not possible.
There are 2 types of text in Classic Shell.
The first group is text that appears in the start menu, tooltips, and such. This is automatically translated.
The second group is the Settings window. To translate it you need to download a DLL from here:
http://classicshell.net/translations/. However at the moment there are no translations for the beta. There is a lot of new text compared to 3.6.8, and it is still being changed, so it will not have translations until the official release.
The third group (I know I said 2 groups, but whatever) is the installer and the help file. At the moment it is only translated in Russian. That's because the Russian translator is awesome