Ah...I guess you are just unfamiliar with grammatical genders. I know, coming from English, grammatical genders is a load of crap - keys, cars, houses, pools have genders - that's just ludicrous. But many European languages have this feature and English is one of the few that does not have. These genders are generally arbitrary: A key is female in french but male in german - like i said, a load of crap. But this is something we have to embrace and get used to while learning a language - their functions, features, history, culture and people :)
I'm not unfamiliar with grammatical genders, & I recognize that there may even be a valid historical reason for same. It's just the scut work of figuring out which nouns get which genders, and trying to determine if there is some logical pattern to it.
I know that English does not have genders in the usual linguistic sense, but that there is still remainders of gender in how we are taught to think; Ships are female, as are cats, but dogs are male, as are horses and (sometimes, but rarely anymore) plows. It's the very arbitrariness of gender in language which makes me confused about it.
I know that with practice I will figure it out. When I spent six months in Norway back in the late 70's I got very good at it, mostly because the dialect where my family lives allows both male and female to be treated the same, so effectively there are only two genders there. Now Duo is teaching them to be separate again and that, in reality, may be my problem.
Sadly, there really is no logical explanation for grammatical genders. They are just what they are, and we have to memorize it.
And it doesn't really help if your native language uses grammatical genders too, because genders in norwegian are different to my native language (et tåg, but en skip. In my language it's just the other way round!)
Isn't there a pattern for grammatical genders? I mean, in Portuguese, for example, we have a general rule that states "when the word finishes with a, then feminine. If it finishes with o, masculine". Of course there are exceptions, but a general rule is quite a guidance.
The general rule is that you have to memorise the noun with its corresponding article, so that you'll always remember the gender. I wish it were simpler!
There are a few rules, but the type of words that take these endings are typically higher level vocabulary, so they're not going to be immediately useful to you:
Masculine word endings: -else, -ning, -sjon, -dom, -het, -isme
Feminine word endings: -ing, -esse, -inne
Neuter word endings: -ment, -tek, -um, -eri
You may recognise some of them as Greek and Latin noun endings, while others are endings used to turn verbs and adjectives into nouns.
Min is used to refer to singular masculine nouns (e.g.,
gutten min) or singular feminine nouns that you've declined as masculine (e.g.,
Mitt is used to refer to singular neuter nouns (e.g.,
Basically, the form of the possessive changes depending on the grammatical gender and number (i.e., singular or plural) of the person or object you're referring to.
The literal translation of the sentence is "The apple of mine is a fruit". That's just how norwegian works, I'm afraid. Give it a few more weeks and you'll get used to it.
Also note that you could also say "Mitt eple er en frukt", but that would put the emphasis on the fact that it's your apple, and not somebody elses.