"Eight little girls jump."
Translation:작은 여자아이 여덟 명이 뛰어요.
Why doesn't it accept 소녀 or 소년? Do Koreans prefer to use 여자아이 and 남자아이 every time they want to say girl or boy?
소녀 and 소년 are generally older than 여자아이 and 남자아이. 소녀 is more like teenage girl, or a young woman and 여자아이 is a child, let's say up to 10~12 years old. Not that 여자아이 literally means 'female child'.
Therefore it's not very natural to say '작은 소녀' if the 소녀 can be even 25 years old. But it is perfectly fine for 여자아이 who is little by the definition.
The same applies to boys of course