The acquisition of communication skills is a dynamic, bidirectional process of interactions between speaker and listener. Children who are unable to meet their daily needs using their own speech require alternative systems to support their communication interaction efforts (Reichle, Beukelman, and Light, 2001). An augmentative and alternative communication (AAC) system is an integrated group of components used by a child to enhance or develop competent communication. It includes any existing natural speech or vocalizations, gestures, formal sign language, and aided communication. “AAC allows individuals to use every mode possible to communicate” (Light and Drager, 1998, p. 1).

The goal of AAC support is to provide children with access to the power of communication, language, and literacy. This power allows them to express their needs and wants, develop social closeness, exchange information, and participate in social, educational, and community activities (Beukelman and Mirenda, 1998). In addition, it provides a foundation for language development and facilitates literacy development (Light and Drager, 2001). Timeliness in implementing an AAC system is paramount (Reichle, Beukelman, and Light, 2001). The earlier that graphic and gestural mode supports can be put into place, the greater will be the child's ability to advance in communication development.

Children experience significant cognitive, linguistic, and physical growth throughout their formative years, from preschool through high school. AAC support for children must address both their current communication needs as well as predict future communication needs and abilities, so that they will be prepared to communicate effectively as they mature. Because participation in the general classroom requires many kinds of extensive communication, effective AAC systems that are age appropriate and context appropriate serve as critical tools for academic success (Sturm, 1998, p. 391). Early interventions allow children to develop the linguistic, operational, and social competencies necessary to support their participation in academic settings.

Many young children and those with severe multiple disabilities cannot use traditional spelling and reading skills to access their AAC systems. Very young children, who are preliterate, have not yet developed reading and writing skills, while older children with severe cognitive impairments may remain nonliterate. For individuals who are not literate, messages within their AAC systems must be represented by one or more symbols or codes. With children, early communication development focuses on vocabulary that is needed to communicate essential messages and to develop language skills. Careful analysis of environmental and communication needs is used to develop vocabulary for the child's AAC system. This vocabulary selection assessment includes examination of the ongoing process of vocabulary and message maintenance.

The vocabulary needs of children comprise contextual variations, including school talk, in which they speak with relatively unfamiliar adults in order to acquire knowledge. Home talk is used with familiar persons to meet needs and develop social closeness, as well as to assist parents in understanding their child. An example of vocabulary needs is exhibited by preschool children, who have been found to use generic small talk for nearly half of their utterances, when in preschool and at home (Ball et al., 1999). Generic small talk refers to messages that can be used without change in interaction with a variety of different listeners. Examples include “Hello”; “What are you doing?”; “What's that?”; “I like that!”; and “Leave me alone!”

Extensive instructional resources are available to school-age children. In the United States, the federal government has mandated publicly funded education for children with disabilities, in the form of the Individuals with Disabilities Education Act, and provides a legal basis for AAC interventions. Public policy changes have been adopted in numerous other countries to address resources available to children with disabilities.

AAC interventionists facilitate transitions from the preschool setting to the school setting by ensuring comprehensive communication through systematic planning and establishing a foundation for communication. A framework for integrating children into general education programs may be implemented by following the participation model (Beukelman and Mirenda, 1998), which includes four variables that can be manipulated to achieve appropriate participation for any child. Children transitioning from preschool to elementary school, self-contained to departmentalized programs, or school to post-school (vocational) will attain optimal participation when consideration is made for integration, social participation, academic participation, and independence. An AAC system must be designed to support literacy and other academic skill development as well as peer interactions. It must be appealing to children so that they find the system attractive and will continue using it (Light and Drager, 2001).

AAC systems are used by children with a variety of severe communication disorders. Cerebral palsy is a developmental neuromuscular disorder resulting from a nonprogressive abnormality of the brain. Children with severe cerebral palsy primarily experience motor control problems that impair their control of their speech mechanisms. The resulting motor speech disorder (dysarthria) may be so severe that AAC technology is required to support communication. Large numbers of persons with cerebral palsy successfully use AAC technology (Beukelman, Yorkston, and Smith, 1985; Mirenda and Mathy-Laikko, 1989). Typically, AAC support is provided to these children by a team of interventionists. In addition to the communication/AAC specialist, the primary team often includes occupational and physical therapists, technologists, teachers, and parents. A secondary support team might include orthotists, rehabilitation engineers, and pediatric ophthalmologists.

Intellectual disability, or mental retardation, is characterized by significantly subaverage intellectual functioning coexisting with limitations in adaptive skills (communication, self-care, home living, social skills, community use, self-direction, health and safety, academics, leisure, and work) that appear before the age of 18 (Luckasson et al., 1992). For children with communication impairments, it is important to engage in AAC instruction and interactions in natural rather than segregated environments. Calculator and Bedrosian noted that “communication is neither any more nor less than a tool that facilitates individuals' abilities to function in the various activities of daily living” (1988, p. 104). Children who are unable to speak because of cognitive limitations, with and without accompanying physical impairments, have demonstrated considerable success using AAC strategies involving high-technology (electronic devices) and low-technology (communication boards and books) options (Light, Collier, and Parnes, 1985a, 1985b, 1985c).

Autism and pervasive developmental disorders are described with three main diagnostic features: (1) impaired social interaction, (2) impaired communication, and (3) restricted, repetitive, and stereotypical patterns of behaviors, interests, and activities (American Psychiatric Association, 1994). These disorders occur as a spectrum of impairments of different causes (Wing, 1996). Children with a pervasive developmental disorder may have cognitive, social/communicative, language, and processing impairments. Early intervention with an emphasis on speech, language, and communication is extremely important (Dawson and Osterling, 1997). A range of intervention approaches has been suggested, and as a result, AAC interventionists may need to work with professionals whose views differ from their own, thus necessitating considerable collaboration (Simeonsson, Olley, and Rosenthal, 1987; Dawson and Osterling, 1997; Freeman, 1997).

Developmental apraxia of speech (DAS) results in language delays, communication problems that influence academic performance, communication problems that limit effective social interaction, and significant speech production disorder. Children with suspected DAS have difficulty performing purposeful voluntary movements for speech (Caruso and Strand, 1999). Their phonological systems are impaired because of their difficulties in managing the intense motor demands of connected speech (Strand and McCauley, 1999). Children with DAS have a guarded prognosis for the acquisition of intelligible speech (Bernthal and Bankson, 1993). DAS-related speech disorders may result in prolonged periods of unintelligibility, particularly during the early elementary grades.

There is ongoing debate over the best way to manage suspected DAS. Some children with DAS have been treated with phonologically based interventions and others with motor learning tasks. Some interventionists support very intense schedules of interventions. These arguments have changed little in the last 20 years. However, the need to provide these children with some means to communicate so that they can successfully participate socially and in educational activities is becoming increasingly accepted. Cumley (1997) studied children with DAS who were provided with AAC technology. He reported that the group of children with lower speech intelligibility scores used their AAC technology more frequently than children with higher intelligibility. When children with DAS with low intelligibility scores used AAC technology, they did not reduce their speech efforts, but rather used the technology to resolve communication breakdowns. The negative effect of reduced speech intelligibility on social and educational participation has been documented extensively (Kent, 1993; Camarata, 1996). The use of AAC strategies to support the communicative interactions of children with such severe DAS that their speech is unintelligible is receiving increased attention (Culp, 1989; Cumley and Swanson, 2000).

In summary, children with severe communication disorders benefit from using AAC systems, from a variety of perspectives. Children with an assortment of clinical disorders are able to take advantage of increased communication through the use of AAC. The provision of AAC intervention is influenced by the child's communication abilities and access to memberships. Membership involves integration, social participation, academic participation, and ultimately independence. A web site (http://aac.unl.edu) provides current information about AAC resources for children and adults.