In fact, English does something very similar. There's a bookshelf, but never a furniture - you can say a piece of furniture if you want to be fancy. There's a

In fact, English does something very similar. There's a bookshelf, but never a furniture - you can say a piece of furniture if you want to be fancy. There's a cow, and cows, but never a cattle, or even cattles. (What do you mean they are uncountable. They are freaking cows.) Then there are crazy stuff like a pair of scissors. (I mean, has anyone seen a scissor?) Somehow native English speakers memorize all of this. At least genders are conceptually easy: given a word, you have one gender. (Though I'm sure there are complications.)