YOU SAID:

My sister is the mother of my father

INTO JAPANESE

妹は父の母

BACK INTO ENGLISH

Sister is father's mother

INTO JAPANESE

姉は父の母

BACK INTO ENGLISH

My sister is my father's mother

INTO JAPANESE

妹は父の母

BACK INTO ENGLISH

Sister is father's mother

INTO JAPANESE

姉は父の母

BACK INTO ENGLISH

My sister is my father's mother