YOU SAID:
why don’t you just be quiet.
INTO JAPANESE
静かにしてみませんか。
BACK INTO ENGLISH
Why don't you keep quiet?
INTO JAPANESE
なんで黙ってないの?
BACK INTO ENGLISH
why aren't you silent
INTO JAPANESE
なぜあなたは黙っていないのですか
BACK INTO ENGLISH
why aren't you silent
That didn't even make that much sense in English.