PHONEME AND GRAPHEME CORRESPONDENCE
A phoneme, as defined in the Longman Dictionary of Applied Linguistics (1985), is "the smallest unit of sound in a language which can distinguish two words." Thus, pan and ban differ only in the contrast of the phonemic consonants /p/ and /b/; and ban and bin differ only in the phonemic vowels /ยต/ and /I/. The English (RP)'s phoneme inventory contains 24 consonants and 20 vowels. The phone is a realization in sound of a phoneme. Interestingly, there are no minimal pairs contrasting dental and alveolar [n] in English. As a result, the difference is not phonemic; rather, the two forms are allophonic of the same phoneme /n/.
A grapheme, in linguistics, is a minimal unit in a writing system. It consists of one or more symbols representing a phoneme. Graphemes are individually related in writing or print to graphs. An individual graph, when compared with another graph or representing a grapheme, is called an allophone.
Were it, however, that things were this simple in the practice of the English language!
The consistency of inconsistencies in English phonology
The problem of phoneme-grapheme correspondences in English continues to baffle linguists as well as EFL teachers. This is not surprising when one considers the inconsistencies found in such correspondences. Clymer (1963) studied 45 phonic generalizations to discover whether they were consistent in the words students encountered in initial reading texts. He found there was a high degree of variability in their reliability. Piper (1983a) selected for further study 19 of the 45 generalizations involving vowels. She concluded that, since ESL students want to learn phonics and the phonics rules available are fairly unreliable, she would examine the generalizations to see which worked and which should be "reformulated to improve their utility".
Bouton (1976, p. 154) stressed that writing is not a simple transposition of the spoken exp...