Phonics is the understanding that there is a predictable relationship between phonemes (the sounds of spoken language) and graphemes (the letters and spelling that represent those sounds in written language). Phonics instruction teaches children the relationship between the graphemes of written language and the phonemes of the spoken language. For example, the sound /k/ can be represented by c, k, ck, ch, or q spellings. Phonics instruction helps children learn and use the alphabetic principle -- the understanding that the sounds of letters can be blended together to produce approximate pronunciations of unknown words. (Put Reading First). Phonics instruction requires the teacher to provide students with a core body of information about phonics rules, or patterns.
Phonics instruction is the medium for children to explore, internalize, and apply this knowledge so that they can gradually achieve greater facility and independence with reading and writing. Phonics helps children attack new words and add those words to their sight vocabularies. Phonics and phonics instruction are a means to the real end: comprehension of written language (Put Reading First).
"All children can profit from quality phonics instruction that is purposefully and meaningfully embedded into the early reading program." (Zimmerman, Padak & Rasinski, 2008)