The English writing system is more complex than other alphabetic languages, but it is predictable:
- 50% of words in English are spelled accurately by sound–symbol correspondence rules alone.
- 36% more are spelled with only one irregularity (usually the vowel sound)
- 10% can be spelled correctly if meaning, origin and morphology and etymology are considered
- fewer than 4% are truly irregular
If half of our English vocabulary can be spelled accurately by sound-symbol correspondence it’s easy to see why grapheme-phoneme correspondences are central to being able to crack the English code and understand our writing system or orthography. Understanding grapheme-phoneme correspondences requires knowledge of the English alphabet and how letters combine in a variety of ways to represent our speech sounds.
In order to teach reading effectively teachers need to understand the difference between the alphabetic principle, letter-sound knowledge, phonics, phonic decoding and orthographic mapping.
Alphabetic principle is an insight rather than a specific skill. It is the conceptual understanding that the letters in the alphabet can be combined in various ways represent our spoken words in writing.
Letter-sound knowledge is secure knowledge of the relationship between sounds (phonemes) and letters (graphemes) along with letter names.
Phonics is the body of knowledge that incorporates letter-sound knowledge and the skills to employ this knowledge to accurately read words. Phonics instruction ensures the beginning reader understands how speech sounds, or phonemes, map to the letters, or graphemes.
Phonic decoding (also known as phonological recoding) is the strategy employed to enable the reader to sound out unfamiliar words and uses the phonemic awareness skills of oral segmenting and blending in combination with letter-sound knowledge.
Orthographic mapping is the cognitive process for to storing words for immediate and automatic retrieval. Orthographic mapping uses knowledge of grapheme-phoneme correspondences to establish a memory for printed words.
Systematic instruction has a clearly planned sequence, introducing new content methodically and cumulatively. Instruction is based on analysis of the complexity of the knowledge and skills to be learned to ensure student understanding.
Explicit instruction is “a systematic method of teaching with emphasis on proceeding in small steps, checking for student understanding, and achieving active and successful participation by all students.” Rosenshine 2012
Incidental instruction highlights elements of language as they appear in the text and does not make use of a predetermined teaching sequence.