An awareness of phonemes is necessary to grasp the alphabetic principle that underlies our system of written language. Specifically, developing readers must be sensitive to the internal structure of words.
If children understand that words can be divided into individual phonemes and that phonemes can be blended into words, they are able to use letter-sound knowledge to read and build words. As a consequence of this relationship, phonological awareness is a strong predictor of later reading success. Researchers have shown that this strong relationship between phonological awareness and reading success persists throughout school.
Early reading is dependent on having some understanding of the internal structure of words, and explicit instruction in phonological awareness skills is very effective in promoting early reading. However, instruction in early reading — especially instruction in letter-sound correspondence — strengthens phonological awareness.
Success in early reading depends on achieving a certain level of phonological awareness. Instruction in phonological awareness is beneficial for most children and critical for others.
from : nowlearnmore.com