YOU SAID:

my mom ate my baby sister's brothers cousin

INTO JAPANESE

私の母は私の赤ちゃんの妹の兄弟のいとこを食べました

BACK INTO ENGLISH

My mother ate my baby sister's brother's cousin

INTO JAPANESE

母は私の赤ちゃんの妹の弟のいとこを食った

BACK INTO ENGLISH

My mother ate my baby sister's brother's cousin.

INTO JAPANESE

母は私の赤ちゃんの妹の弟のいとこを食びました。

BACK INTO ENGLISH

My mother ate my baby sister's brother's cousin.