Complex sentence: At that time, most females were illiterate and considered as the property of men and women who learned Nüshu can share their joys and sorrows, hopes and fears with their sworn sisters whom they communicated in their own language.
Split into simpler sentences: At that time, most females were illiterate and considered the property of men. Women who learned Nüshu could share their feelings and experiences with other women, with whom they communicated in their own language.