Speech and Language Disorders

Description

Both language and speech are essential components of verbal communication. Language refers to a set of signs, sounds, or symbols that are recognized as having meaning when produced in the context of a verbal community. Speech, on the other hand, is the mechanical process by which a speaker actually vocalizes the sounds that we call language. Although humans can express language through many media (vocal, written expression, motor movements), speech is by far the most common.

Within the broad topics of speech and language, various subcomponents exist. For example, language involves the use of both simple rules, such as how letters are combined to form functional words (phonology), and also how words interact with context to [Page 1542]produce meaning (pragmatics). Similarly, components of speech are both simple (e.g., the production of monosyllabic sounds) and complex (e.g., producing fluctuations in the physical properties of sound, such as the pitch, thereby changing the meaning of an utterance). Considering these complexities, disordered speech and language present in various ways. Although different professions utilize different systems to classify speech and language disruptions, the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) includes four main categorizations of speech and language disorders: (a) expressive language disorder, (b) mixed receptive-expressive language disorder, (c) phonological disorder, and (d) stuttering. The first two categories represent disordered language development or language production, and the latter two categories represent disruptions in the production of speech. Most classification systems do not include a category for purely receptive language deficits because receptive deficits rarely occur in the absence of expressive language difficulties.

Expressive language disorder is characterized by a deficit, as measured by standardized assessment instruments, in expressive language development relative to receptive language development and nonverbal intellectual abilities. The specific difficulties that comprise the deficit may include, but are not limited to, difficulty learning new words, impoverished vocabulary, grammatical errors, omissions of parts of a sentence, limited use of sentences, difficulty producing sentences of developmentally appropriate length or content, and syntax errors.

Mixed expressive-receptive language disorder is similar to expressive language disorder but includes deficits in receptive language development relative to nonverbal intellectual abilities. Students with mixed expressive-receptive language disorder show evidence of the aforementioned expressive impairments and also demonstrate deficits in the comprehension of words or sentences. Students with these disorders commonly present with other language or speech difficulties (e.g., difficulties in the production and rhythm of speech).

Typically, language deficits are evident in early childhood, but mild forms and the significance of the impairment may not be readily apparent until adolescence, when language becomes more complex. Language disorders occur in approximately 3% to 5% of children, with expressive language disorder being the more common of the two. Many children with a language disorder, however, outgrow the deficits. In fact, about half of children with expressive language disorder develop normal language abilities by adolescence. Although the prognosis for spontaneous recovery in mixed expressive-receptive language disorder is not as promising, many children with this disorder develop normal language abilities as well.

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