Who communicates with the Lord of the Flies?

Answer: Simon

Explanation: Simon is on his own in the forest, and sees the pig head on the stick that jacks group put up for the 'beasty' He has a medical condition but we are not sure what it is and it it told to us as he acts differently to a normal person. He is very dehydrated, and starts hallucinating and talking to the pigs head, or the lord of the flies.

simon talks to him. he is "batty" before he talked to it, it said something about him being thirsty or hungry or something like that which gives reason to believe that the entire conversation was a hallucination especially since he went unconscious as soon as it was done