Who is the only one who may interrupt the speaker when he is holding the conch in Lord of the Flies?

To quote from the meeting in chapter 2: Fire on the Mountain, Ralph said... "...I'l give the conch to the next person to speak. He can hold it when he's speaking... And he won't be interupted. Except by me."
Whoever is holding the conch gets to speak and everyone else must listen.
In Lord of the Flies the conch is symbolic of the boys hope for rescue.
To quote from the meeting in chapter 2: Fire on the Mountain, Ralph said... "...I'l give the conch to the next person to speak. He can hold it when he's speaking... And he won't be interupted. Except by me."