More than one million of the students served in the public schools' special education programs in the 1997-98 school years were categorized as having a speech or language impairment. This estimate does not include children who have speech or language problems secondary to other conditions such as deafness. Language disorders may be related to other disabilities such as mental retardation, autism, or cerebral palsy. It is estimated that communication disorders (including speech, language, and hearing disorders) affect one of every 10 people in the United States.
As defined by the American Speech-Language-Hearing Association: A language disorder is the impairment of deviant development of comprehension and/or use of spoken, written, and/or other symbol system. The disorder may involve (1) the form of language (phonologic, morphologic, and syntactic systems), (2) the content of language (semantic system), and/or (3) the function of language in communication (pragmatic system) in any combination (American Speech and Hearing Association, 1982).
Speech and language disorders refer to problems in communication and related areas such as oral motor function. These delays and disorders range from simple sound substitutions to the inability to understand or use language or use the oral-motor mechanism for functional speech and feeding. Some causes of speech and language disorders include hearing loss, neurological disorders, brain injury, mental retardation, drug abuse, physical impairments such as cleft lip or palate, and vocal abuse or misuse
Language disorders can be developmental (i.e. present from early childhood) or they can be acquired as the result of surgery, a stroke, an accident or old age. In certain cases, this had a marked effect upon their ability to communicate in speech or in writing (field, 2003: 53).
