One common theme found among the Celtic nations describes a race of diminutive people who had been driven into hiding by invading humans. They came to be seen as another race, or possibly spirits, and were believed to live in an Otherworld that was variously described as existing underground, in hidden hills (many of which were ancient burial mounds), or across the Western Sea.
In old Celtic faery lore the sidhe (fairy folk) are immortals living in the ancient barrows and cairns. The Tuatha de Danaan are associated with several Otherworld realms including Mag Mell (the Pleasant Plain), Emain Ablach (the Fortress of Apples or the Land of Promise or the Isle of Women), and one of the most well known Tir na nÓg (the Land of Youth).
Perhaps they are fairies.
Angels have spoken to many biblical and other non- biblical characters throughout history. Usually an angels will talk to only one person, but on occasion is documented to have spoke to a group of people.
Demons are highly possible, what better way to tempt or torture a soul then when it is by itself and vulnerable. Its possible and the king of the demons Satan or Lucifer (whichever you may prefer) tempted Eve when she was by herself into eatting the fruit.
God or Satan
It could be possible that God or Satan was the ones talking. As documented and told; God usually speaks in whispers (or at least I believe so), when talking to present day man. Perhaps Satan does the same thing to seem like God, after all we cannot see what we are hearing.
4) So are the voices good? or are the voices bad?
A relevant question. But I would assume that the answer would depend on what the voices were. For instance other scenario's of the voices could be angels, Demons, Satan and even God, its difficult to say. That is up to you.
5) Other theories
Well, the first "other" theory should be psychological. When a person is by him/herself there mind could and often will play tricks on you. If you are dehydrated, scared, adrenaline flowing (which increases senses drastically), lost which can lower your hope and spirit, which makes you sort of hallucinate or a small sense of shock.
Other unknown psychological illnesses can cause this and a psychological position (especially stressful ones) could cause other unwanted psychological issues.
Of course! The most Obvious! Hunters, poachers, and other hikers or journeymen could be the voices being heard, that is almost certainly a possibility. But then why, would no one approach someone who is screaming for help in the middle of jungle, woods, or forest? Poachers actually love prisoners (and not in a good way), hunters are always helpful to those who need it and a fellow hiker or journeymen would help, unless they are cruel. Its possible.
Its certainly possible that some sort of bug could be prodcuing voices or whispers, much like grasshoppers or even beatles. Its a possibility, but I'm not sure, while it sounds like a very sound theory, it just does not seem right.
Are they good? What are they? Why do they occur?
I hope this helps those who were interested in this type of event. I also hope that this has opened a new doors in other peoples minds to become interested in this type of event. Its a very interesting phenomena that deserves its own respect. So simply put, what are they? That my friends is up for you to decide.
Also please if you have your own theory, POST it, don't hesitate and think twice about it.