*Editor's Note: The following column is just a theory. The views, events, and situations that I mention are not necessarily true. They are just ideas I have based on what I have seen in the various Seasons of Lost. Please do not take these as rumors or spoilers. But if they do turn out to be true, that would be kinda cool!
"Have you seen these others?"
"No... but I hear them... they whisper."
It was this quotation from Season 1 that introduced us to the Others. It would take several seasons for us to finally see who these others were, and finally in Season 3 we see how they really leave- in the former Dharma Barracks.
However, we have always heard these whispers. On TV, they are un-audible. But there are crazy people out there who actually have the patience to sit there and use special sound equipment to see what the whispers say.
All you have to do is look up on Lostpedia.com "The Whispers Transcripts" and you will find out what these people, whoever or whatever they are, discussing the events duringthat scene, talking about the people in the scene, or just spewing out random info. But what are these whispers? Who is speaking them? Why are they there? And why do they announce the Others are arriving?
As we saw in a flashback in Season 5, Ben told Danielle to run whenever she heard whispering. This led her to believe it was a warning of the Others. And this she told to Sayid, who told to the Losties.
But what if Danielle misunderstood? What if Ben warned her because said Whispers could help her?
I think the Whispers that we hear are actually the dead talking. The most obvious reason for this is that, in one episode when Shannon was in the jungle, a whisper said "Hi, sis". This leads me to believe that Boone was talking, but he was dead.
And we all know how much the Others love thier dead. The dead must be burried, but for what reason we do not know. Whether it has to do with the fact that Esau evidently likes to take the form of the dead or if there is another reason we're not sure. But anyway, the dead love to communicate with the Islanders.
Now, granted, really can't explain why or how the dead Whisper. But my theory is that the dead do Whisper, to warn the people, help them, or perhaps even put them in danger.