This is another special developmental disorder. It is characterized by uncontrollable speed of speech, which results in truncated, dysrhythmic, and often incoherent utterances. Omissions of consonants, elisions, improper phrasing, and inadequate intonation occur. It is as though the child were too hurried to take the trouble to pronounce each word carefully and to compose sentences. Cluttering is frequently associated with other motor speech impediments. Speech therapy (elocutionary) and maturation may be attended by a restoration of more normal rhythms.
Milder speech defects are common in preschool children, having an incidence of up to 15 percent. There are several varieties. One is lisping, in which the s sound is replaced by th, for example, thimple for simple. Another common condition, lallation, or dyslalia, is characterized by multiple substitutions or omissions of consonants. Milder degrees consist of difficulty in pronouncing one or two consonants that give the impression of “baby talk” and are referred to as “infantilisms.” For example, the letter r may be incorrectly pronounced, so that it sounds like w or y; running a race becomes wunning a wace or yunning a yace. In severe forms, speech may be almost unintelligible. The child seems to be unaware that his or her speech differs from that of others and is distressed at not being understood. More important is the fact that in more than 90 percent of cases, the articulatory abnormalities disappear by the age of 8 years, either spontaneously or in response to speech therapy. The latter is usually started if these conditions persist into the fifth year. Presumably the natural cycle of motor speech acquisition has only been delayed, not arrested. Such abnormalities, however, are more frequent among developmentally delayed children than in normal children; with cognitive defects in general, many consonants are persistently mispronounced.
Another disorder is a congenital form of spastic bulbar speech, described by Worster-Drought, in which words are spoken slowly, with stiff labial and lingual movements, hyperactive jaw and facial reflexes, and, sometimes, mild dysphagia and dysphonia. The limbs may be unaffected, in contrast to cerebral palsy.
The mechanical speech disorder resulting from cleft palate is easily recognized. Many of these patients also have a harelip; the two abnormalities together interfere with sucking and later in life with the enunciation of labial and guttural consonants. The voice has an unpleasant nasality; often, if the defect is severe, there is an audible escape of air through the nose.
The aforementioned developmental abnormalities of speech pattern are only sometimes associated with disturbances of higher-order language processing. Rapin and Allen have described a number of such disturbances. In one, which they call the “semantic pragmatic syndrome,” a failure to comprehend complex phrases and sentences is combined with fluent speech and well-formed sentences lacking in content. The syndrome resembles Wernicke or transcortical sensory aphasia (Chap. 22). In another, “semantic retrieval-organization syndrome,” a severe anomia blocks word finding in spontaneous speech. A mixed expressive–receptive disorder may also be seen as a developmental abnormality; it contains many of the elements of acquired Broca’s aphasia (Chap. 22). Recently, a category of “specific language impairment” has been created to encompass all failures to acquire language competence despite normal intelligence.