Phonemes are the units of sound (speech) which distinguish one word from another in a particular language, they are discrete abstractions. In most varieties (accents and dialects) of spoken English there are about 24 consonantal phonemes and 20 vowel phonemes (altogether 44 phonemes), but only 26 letters in writing. To learn all the phonemes in English, it would be better to use the IPA, which has a unique letter for every phoneme in English, unlike the English alphabet. The development of phonological representations for words and their parts is a major step in learning a spoken language.
- Concise Oxford English dictionary, p1027.