"Ei" isn't showing up for feminine words, for me.
Just started, and words like "kvinne" and "jente" are shown with "en". Don't know if this is a bug, so not reporting it, just felt like mentioning that.
Apparently, the team's already decided to default to a "moderate" form of bokmål as defined by NTB (see the first post at http://incubator.duolingo.com/courses/no-BO/en/status). Regarding nouns, this usually means that the ones with optional gender will be masculine (en) by default.
I personally prefer ei too, but people from certain regions (typically the areas in and around Bergen and Oslo) don't necessarily. Sure, I want people to endorse the same (rather implicit and vague) cultural and geographical lingo-symbols as I do, but I have no rational argument for one sounding better or more correct than the other.
That's not to say we can't discuss conjugations that - albeit correct - may sound very regional, conservative, radical or unnatural in spoken conversation (e.g. jenten, which sounds normal if you have a Hordaland/Bergen accent, and very conservative otherwise) in the forums for the benefit of intermediate and advanced students :)
This is correct. ^
We use 'ei jente, jenta' rather than 'en jente, jenten', and show examples of a few others, but aside from that we default to the 'en' versions. 'en kvinne, kvinnen' is much more common than 'ei kvinne, kvinna' in written form.
We aim to accept all sidestilte former for all words, but there are -a lot- of them in Norwegian so it's definitely a work in progress. Please report if your preferred and acceptable way of writing Norwegian is not accepted as one of the answers.