What is it that Simon had said that Ralph recalls in Chapter 11 of Lord of the Flies? What makes it so signifigant?
I am a little thrown off by the wording of your question...I think I know what you are inquiring about, though. I believe that you are asking about what Ralph remembers from Simon and why it is significant. If this is the case, then I have an answer : )
Let's set the scene:
Piggy has just been killed by an Indiana Jones style bolder that rolls into him and knocks him off the cliff. The other little heathens have started to throw spears at Ralph:
Viciously, with full intention, he hurled his spear at Ralph. The point tore the skin and flesh over Ralph’s ribs, then sheared off and fell in the water.
Ralph takes off running to avoid the barrage.
It is at this point that he remembers Simon's hiding spot by the severed pig's head:
He saw the headless body of the sow and jumped in time. Then he was crashing through foliage and small boughs and was hidden by the forest.
This is what he remembers from Simon, the boy's secret hiding space.
Why is it significant? Because had he not been able to conceal himself the hunters would have turned him into a human kabob. Instead, because he is able to conceal himself:
The chief stopped by the pig, turned and held up his hands. “Back! Back to the fort!”
So there you have it. If I have interpreted your question correctly, the answer is "the fort" and "because it keeps him from getting pin-cushioned."