"What is an apple?"
Translation:Hva er et eple?
"Do you have to learn specific genders for nouns?"
Sadly, yes. There are no definite rules which noun takes which gender. When you learn vocabulary, don't learn "book - bok, woman - kvinne", learn "book - ei bok, woman - ei kvinne, child - et barn", and so on.
Note, that in bokmaal you can use any feminine noun as a masculine one. So "En kvinne" and "ei kvinne" are both correct. However, I think it is worth it to learn which nouns are actually feminine, so you won't be surprised if you encounter the feminine form "in the wild".
Wow, that was 11 months ago, but I think what I meant was: I got surprised by certain words appearing in their feminine form. "Boka" for example. Up until then I have only ever seen "booken", so it took me a few seconds to figure out that "boka" also means "the book". So, to avoid confusion it's always helpful to learn which words are feminine and which ones aren't. "Boka" is correct as is "boken", but for masculine words "gutta" would be wrong, only "gutten" is correct.