The Whispers are voices heard in the jungle. The Whispers are the voices of people who have died, but remained bound to the Island, unable to move on. Michael Dawson becomes one of the Whisperer and appears to Hurley, explaining that he is bound to the Island, unable to move on after murdering Libby and Ana-Lucia. (Everybody Loves Hugo)
At various points in the series whispering voices have been heard by the characters, with no visible source of origin. Rousseau claims these voices are of the Others. They seem to have a connection with the visions; before Ana Lucia shot Shannon who was chasing an image of Walt, they heard the whispering around them. At the end of season 3, there was whispering before Walt showed up at the mass grave.
| Sayid Jarrah
After escaping the capture of Danielle Rousseau, Sayid heads into the jungle heading back to his camp, when he begins to hear whispering voices surrounding him. Sayid later brushes this off as the wind playing tricks on him and that he was disoriented.
| James "Sawyer" Ford
After a boar raided Sawyer's tent, he chased after it into the jungle. When it fled, he started to head back to the camp when he suddenly heard whispers. One of them was the voice of Frank Duckett saying "It'll come back around", which is what Duckett said after he was shot. Sawyer heard the whispering again later in the day when he was pursuing the boar, and once again heard the voice of Duckett say "It'll come back around".
| Shannon Rutherford
While searching for Vincent in the jungle with Sayid, Shannon trips after trying to follow Sayid and heard whispers surrounding her. As she turns in all directions to see who it is, she suddenly sees Walt standing in front of her, soaking wet, and speaking backwards saying "Don't push the button. The button's bad.".
| Michael, Jin and the Tailies
After carrying the injured and unconscious Sawyer up a steep cliff, Ana-Lucia, Mr. Eko, Michael, Libby, Jin and Bernard find themselves at the top of the cliff, however Cindy is absent. Ana says that she is going to go after her, but Eko says that they should stick together, which causes Ana to place the blame of Cindy's disappearance on Eko. Whispers begin to surround them, and Ana draws her gun, as they all begin to panic, Ana advises them to run.
| Sayid and Shannon
Shannon heads into the jungle to search for Walt when she again sees him speaking backwards. Sayid follows her and the two find themselves deep in the jungle. When Shannon asks Sayid to believe in her, Sayid says that he does and that he loves her. The two then hear the whispers around them, and Sayid and Shannon see Walt near them, he says "Shhh" and runs off. Shannon pursues him, and is accidentally shot by Ana-Lucia.
| Jack, Kate, Sawyer, Hurley, and Michael
Jack reveals to Kate, Sawyer, and Hurley that Michael is a traitor, which Michael admits. Jack reveals Sayid's plan, but it does not work - Sayid sets off a signal fire from the Others camp, but it is miles away; Michael has not led the group there. All of a sudden, the sound of whispers surrounds them. Everyone draws their weapons, but it doesn't matter. They are all suddenly ambushed, bound and gagged, and taken to the long dock.
| Benjamin Linus
While heading towards the Sonar Fence, looking for his mother, Benjamin Linus hears whispers surrounding him immediately before she appears to him in a vision. The whispers were once again heard by Ben after he headed across the sonar fence, right before he encountered Richard Alpert.
| John Locke
After being shot by Ben and left for dead in the mass grave, John Locke heard whispers right before he prepared to pull the trigger on a gun and kill himself. This action was halted by Walt, who appeared and informed Locke that they had work do to.