It's basically "to be". The subject is assumed in this sentence. So "boy to be" is "he is a boy"
So Rina issa is "She is a girl" but Taoba issa is "It's a boy" -- shouldn't "It's a girl" and "He is a boy" also be correct?
It should accept those translations too. Report it if they aren't being accepted yet.
seems so. Just like in Chinese where HE and SHE is depicted as the same word "TA"