The American Federation of Teachers' article, "Waiting Rarely Works: Late Bloomers Usually Just Wilt," says that poor early readers are lacking a basic literacy skill: phonemic awareness.
The primary skill many poor early readers are lacking is phonemic awareness - the ability to hear and understand individual letter sounds. Many poor readers have trouble improving their reading skills because they do not understand the basic sounds that make up words, meaning they are not able to decode unknown words. Children need to understand the connection between letters and the sounds they make alone and connected to other letters. This allows them to blend together letters sounds to be able to sound out unfamiliar words.