In Chinese, the naming conventions for every member of the family is dependent on their gender, whether the relationship stems from the father or the mother’s side, and their age in relation to you or your parents.
For example, the concept of an “aunt” is dependent on whether the aunt is directly related to either the mother’s or the father’s side, whether they are older or younger, and whether they are siblings to your parents or married into the family.
Another example, my dad’s younger sister’s son would have a different name (a variation of the concept of cousin), than if he was the son of my dad’s older sister. And that would still be different than if he was the son of my dad’s older brother.
Still with me?
Anyway, when this is all too much, go Dutch. In the lowlands, the words neefje and nichtje, which covers not only the ideas of nephew and niece, but also cousins of the same sex. That’s to say, in a cross-generational sweep of generalization, a female cousin of yours bears the same concept as a niece, and a male cousin of yours is the same as a nephew.
As a result, most Dutch have trouble with the concept of cousins, which I suppose, in a familial sense, is probably just as remote as niece and nephews.