YOU SAID:

The thing is that if they start speaking the class won't stop

INTO JAPANESE

問題は、彼らが話し始めてもクラスは止まらないということです

BACK INTO ENGLISH

The problem is that the class doesn't stop when they start talking

INTO JAPANESE

問題は、彼らが話し始めてもクラスが止まらないことです

BACK INTO ENGLISH

The problem is that the class doesn't stop when they start talking