What does Piggy keep having to shout to Ralph and what effect does this have in the story?

Piggy is frightened by the body of the sow.... he afraid..... period. He keeps calling to Ralph because he afraid he'll be left behind. There's also the fact that Piggy can't see without his glasses. Piggy's cried made Ralph's demands for his glasses a joke. They caused the hunters to laugh at the boys. In essence, any power Ralph still had on the island dissipated during those moments.