Abstract
The phonemic system of any language is the basis for all the higher order linguistic structures which make up the complete language system. Language-users carry in their brain a considerable store of information about all levels of any language they are able to employ; at the phonological level, this includes not only the inventory of phonemic units, but also the rules governing the combination of phonemes into morphemes, the sequential probabilities operative in phoneme strings, the correspondence rules linking acoustic cues with phonemic categories, phonemic categories with articulation and articulation with acoustic cues. To say that someone knows English, for example, implies that he can operate with the 40-odd phonemic units that make up the English phonological system and in normal circumstances means that he can receive and understand messages sent to him in English and can himself generate such messages. It must be emphasized, however, that the capacity to take in spoken messages is itself enough to show that the phonemic system is fully developed in the brain of the language-user, even where the capacity for speech is absent. This condition is found, for example, in the case of some severely spastic subjects who are incapable of making the movements required for speech but who can understand anything said to them, and in cases of other kinds of neurological Hefert like rhnse seen in the case examined hv MacNeilafre. Rnotes anH nhnse f to STY
The phonemic system of a language is a set of linguistic units which forms the basis for higher levels of language structure. Knowledge of the system develops in the child during the language-learning period and is normally accompanied by development of the capacity for differentiating articulations. It is necessary, however, to distinguish the phonemic units from the articulations which correspond to them.
The child's language at any stage is not an imperfect version of adult language; it is itself a complete functional system which is capable of expansion. At the phonological level, the child begins with a restricted system of two or three units and the framework of the system expands until, by the age of about five years, the child has developed the complete adult system of about forty units (in English).
Development of the phonemic system implies also the developing of appropriate acoustic cues which are used in both the decoding and the encoding of speech.