Phoneme

The smallest unit of meaningful speech sound used to distinguish words and morphemes in a language (e.g., in English, sounds typically made by the letters m and n are separate phonemes distinguishing words such mail/nail, or met/net).  Thus,it is a difference in soundthat makes a difference in meaning, with a range of sounds being treated as thesame sound.  The word ‘cat’ has three morphemes and so does the word ‘thought’.  It also signals a meaning change between words (e.g., ‘bat’ and ‘bag’ differ in their final phoneme).  A phoneme is abstract concept or category (you cannot see, touch, or hear a phoneme but you can point to instances) and language specific. There are 44 phonemes in American English.  Where English speakers distinguish two phonemes [ lid/rid ], speakers of other languages may hear only one. For example, R is not distinct from L in Japanese. 

See Alphabet, Alphabetic writing system, Babbling, Decoding ability, Diagraphs, Doublets (or geminates), Fricative, Grapheme, Grapheme-phoneme correspondences, International Phonetic Alphabet, Irregular words, Morpheme, Orthographic reading skills, Orthography, Phoneme, Phonemic mastery, Phonics, Speech development, Stimulus-driven development