> Since I can replace "bahasa" with "english" and have the document
> compile (apparently) successfully, there would seem to be no
> /a priori/ reason why "bahasa" cannot be used in the same way. It
> is no more (and no less) ambiguous than "english", which may refer
> to British English, Australian English, American English and so on.
What kind of reasoning is that? The word "badger", which may refer to
Honey badger, American badger, European badger, amongst others, is no
more (and no less) ambiguous than "english". Do you expect than
you can thus use "badger" as a document class option?
Arthur