This is a new development in farsi. ha is from the middle person iha, which ultimately derives from the indo-iranian plus -s (same as in english). s->h is cha

This is a new development in farsi. ha is from the middle person iha, which ultimately derives from the indo-iranian plus -s (same as in english). s->h is characteristic of indo iranian in general and iranian in particular. an in middle person (which comes from another indo-iranian plural an) means this particular thing in middle person. In farsi this converted into general vs. living.