I also wonder if there is not more than one set of Others. I rewatched the episode in which Jin and Eko are hinding in the ground cover and the Others are walking back and forth. The teddy bear being dragged by the string is not the same one that Emma had. (that may be a production goof) Also, all those legs appeared to be from grown ups so the kids weren't with them.
So my question is where do you think the whispers come from?
Are they generated by the Hatch others mechanically? Are they the jungle
others and they are whispering from somewhere close by - hidden
from the survivors - Rousseau has been hearing them for years.

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