YOU SAID:

My grandma is my mothers mother, I am my mothers son.

INTO JAPANESE

私のおばあちゃんは私の母親の母、私の母の息子。

BACK INTO ENGLISH

My grandmother is the mother of my mother, my mother's son.

INTO JAPANESE

私の祖母は私の母、私の母の息子の母です。

BACK INTO ENGLISH

My grandmother is the mother of the son of my mother, my mother.

INTO JAPANESE

私の祖母は私の母、私の母の息子の母です。

BACK INTO ENGLISH

My grandmother is the mother of the son of my mother, my mother.