The whispers = time travel?
Just thinking about the recent time skips the island has been going through. What we see from the perspective of those traveling through time is a bright light and a whooshing sound. Hold that thought.
What strikes me about the nature of these time skips as Shanimal pointed out here, is that they tend to happen when someone has an important message to pass on.
Other times we’ve seen messages being passed on only for the messenger to disappear as quickly as they came: Walt interrupting John’s suicide bid and Harper appearing in the forest to tell Juliette to go to the Tempest are two that spring to mind.
These times the messenger has usually been accompanied by the eerie whispers we puzzle over so much.
So my theory: The time traveler experiences a blinding light, while the ‘temporal native’ (for want of a better term) hears whispers.
Could it be that from Richard’s perspective, just after Locke told him to go witness his birth, instead of a blinding light and a whooshing sound he heard whispers and Locke was gone? Similarly could it be that when Harper visited Juliette (from her perspective) there was a blinding light and a whooshing sound?
If I’m right on this one, that would mean that Walt returns to the island at some point (with the O6?) and skips back to where John is lying in the Dharma pit to deliver his message, and likewise Harper skips through time to visit Juliette.
Can anyone think of any other examples of whispers preceding a message?