I remember a discussion whether ConTeXt's "Norwegian" is Bokmål or Nynorsk (I don't understand any and don't know the difference)
Yes, over one year ago. The discussion started on the dev-context list and subsequently made a brief appearance here (http://www.ntg.nl/pipermail/ntg-context/2007/023834.html). Not much has been done since then; it sure would be good to read over that discussion and sum it up in a patch.
The same goes for "Spanish" (Catalan, other...)
The problem is different here: if you say "Spanish" it really means Castilian (ISO 639-1 'es', ISO 639-2 and 639-3 'spa'), not Catalan (nor Galician or Asturian, for that matter) -- unless otherwise specified, of course. "Norwegian", on the contrary, is really ambiguous and can be used for both the official languages of Norway (although in the mind of many people it will mean Bokmål alone, I suspect). Arthur