YOU SAID:
Jett has a small brain and is dumb
INTO JAPANESE
ジェットは脳が小さくて馬鹿です
BACK INTO ENGLISH
Jet has a small brain and is stupid
INTO JAPANESE
ジェットは脳が小さくてバカだ
BACK INTO ENGLISH
Jet has a small brain and is stupid
That didn't even make that much sense in English.