develop any functional speech to the development of functional but idiosyncratic use of spontaneous speech and language (Lord and Paul, 1997). One-third (Bryson, 1996) to one-half (Lord and Paul, 1997) of children and adults with autism do not use speech functionally. For both verbal and nonverbal individuals, impairments in social or pragmatic aspects of language and related cognitive skills are the most salient (Wetherby et al., 1997).
Research over the past decade has identified core communication deficits in children with autism that fall into two major areas: joint attention and symbol use (Dawson et al., 1990; Kasari et al., 1990; McArthur and Adamson, 1996; Mundy et al., 1990; Sigman and Ruskin, 1999; Stone et al., 1997; Wetherby et al., 1998). Joint attention reflects difficulty coordinating attention between people and objects and is evident by deficits in orienting and attending to a social partner; shifting gaze between people and objects; sharing affect or emotional states with another person; following the gaze and point of another person; and being able to draw another persons’ attention to objects or events for the purpose of sharing experiences.
Symbol use reflects difficulty learning conventional or shared meanings for symbols and is evident in deficits in using conventional gestures; learning conventional meanings for words; and using objects functionally and in symbolic play.
Joint attention has been found to be a significant predictor of language outcome. Mundy et al. (1990) found that measures of gestural joint attention (e.g., showing or pointing to direct attention) at initial testing were a significant predictor of language development 1 year later for preschool children with autism. The failure to acquire gestural joint attention appears to be a critical milestone that impairs language development and an important target for early communication intervention.
Similarly, children with autism do not compensate for their lack of verbal skills with gestures; they show limited gestural use, both in quantity and quality. They predominantly use primitive motoric gestures to communicate (i.e., leading, pulling or manipulating another’s hand). They lack the use of many conventional gestures, such as showing, waving, pointing, nodding the head and symbolic gestures depicting actions (Loveland and Landry, 1986; McHale et al., 1980; Stone and Caro-Martinez, 1990; Stone et al., 1997; Wetherby et al., 1998; Wetherby et al., 1989).
Moreover, in this population, there is much variability in the capacity to use vocal communication which likely contributes to the wide range of verbal skills. Some children with autism have been found to use a limited