Вот что по поподу шепота написали в лостопедии:
The whispers are an audible events that often precede the appearance of an Other. While searching for his mother in the jungle, Ben Linus heard whispers coming from an unknown source, only to meet Richard Alpert minutes later.
A week after Rousseau delivered her child she heard Whispers coming from the jungle, that night they took her child from her; she never saw one of them. After Sayid left Rousseau’s camp and headed back for his own he too heard whispers in the jungle when traveling back to camp, he brushed it off as though it was the wind playing tricks on him.
Sawyer heard the whispers in the jungle as well after an attack from a boar in his tent; he heard them again the next day when he ventured out into the jungle. When Sayid and Charlie discovered Rousseau with the infant Aaron alone at the black smoke, she explains that she heard whispers in the jungle and they said they were coming for the boy.
When Shannon and Sayid were in the jungle searching for Vincent, Sayid chased after Vincent leaving Shannon alone. While there she heard whispers from all around her, and then witnessed a soaking wet Walt. When Shannon and Sayid are in the jungle searching for Walt, they begin to hear whispers, and then Walt appears to Shannon for a third time. When the Tail Section survivors are traveling back to the Fuselage camp, Cindy disappears and they hear whispers coming from all around them, which is something they had never heard before an attack, in an act of panic, Ana-Lucia kills Shannon mistaking her for one of “them”.
Если переводить дословно, то шепот на острове слышен тогда, когда Другие близко, должны появиться или могут появиться... Для некоторых моментом это не очень подходит... Но! Возможно, шепот возникает перед каким-то явлением, к которому можно отнести не только Других. Т.е. помимо Других есть что-то еще, на них похожее по своей сути, что вызывает шепот. Хм...