Language Disorders

Basics of the Linguistic System

To understand language disorders, the multifaceted nature of the language system itself must be understood, because any or all aspects of it may be impaired. The language system is often thought of as arising out of the intersecting components of form, content, and use. The form of language comprises small units that combine to create larger ones, and it is governed by tacitly understood rules for which combinations are permissible and which are not. The smallest unit of an oral language is a sound, or phoneme. Language disorders may, but do not always, include an impairment of the sound system. Even if children do not have difficulty in producing the sounds of their language, they may have difficulty segmenting and recognizing those [Page 566]sounds as individual units. Awareness of these sound units forms the foundation of phonological awareness, which in turn is the most reliable predictor of early reading success. Phonemes are combined according to language-specific rules to create a slightly larger unit, the morpheme, the smallest unit that carries meaning in a language. A morpheme may be either what is commonly considered a word, for example, jump, or what is typically thought of as the prefixes or suffixes that shade the meaning of a word. For example, when the past tense suffix -ed is added to jump (i.e., jumped), the meaning of this word is shaded to reflect not only the action but the time frame in which it occurred. Children with a language disorder have particular difficulty acquiring morphemes. Morphemes are then combined in larger units to form the grammar or syntax of a language. These units are commonly thought of as simple sentences, or when embedded into one other, a complex sentence. Thus, the form or structure of the language within which we express our ideas to others is completed. The earliest emerging sentences are two-word combinations (e.g., “want cookie”), and late onset of this near-universal stage of language acquisition is often one of the first signs of a language disorder. The potential of a language's form as a powerful means of expression is realized once it intersects with its content or meaning, for without ideas about the world or internal desires to express, the form of language is empty. The linguist Noam Chomsky illustrated this point in his now famous sentence, “Colorless green ideas sleep furiously,” exemplifying the notion that phonemes and morphemes may be combined into a sentence that has followed all the rules of a language but expresses nothing. The content component of language, or the ideas we hold about ourselves and other people and things in the world, both draw upon and contribute to the child's conceptual development. Reduced or impoverished vocabulary development is often part of a language disorder.

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