YOU SAID:
Hey mate. Why are you not dancing?
INTO JAPANESE
なぜ踊ってないの?
BACK INTO ENGLISH
Why aren't you dancing?
INTO JAPANESE
あなた達も踊ったら?
BACK INTO ENGLISH
Why aren't you guys dancing?
INTO JAPANESE
あなた達も踊ったら?
BACK INTO ENGLISH
Why aren't you guys dancing?
That didn't even make that much sense in English.