YOU SAID:
Kevin is a big dumb dumb
INTO JAPANESE
ケビンは大のバカです
BACK INTO ENGLISH
kevin is a big idiot
INTO JAPANESE
ケビンは大バカだ
BACK INTO ENGLISH
kevin is so stupid
INTO JAPANESE
ケビンはとても愚かです
BACK INTO ENGLISH
kevin is so stupid
That didn't even make that much sense in English.