90 The Acquisition of Sign Language by Deaf Children with Autism Spectrum Disorder Aaron Shield and Richard P. Meier Introduction Autism spectrum disorder (ASD) consists of a set of neurobiological developmental disorders characterized by communicative and social deficits as well as repetitive, stereotyped behaviors. 1 In this chapter, we use the terms ‘ASD’ and ‘autism’ interchangeably; although ‘autism’ is not a clinical term, it is the term popularly used to refer to the range of disorders found in ASD. The language deficits of hearing children with autism are well docu- mented, and can range from the very mild in highly fluent speakers to the very severe in children with a total absence of productive spoken language. For those children who do acquire speech, the most common characteristics of autistic language include echolalia (echoing the utterances of others), pronoun reversal, idiosyncratic language use and neologisms (the creation of new words), difficulty with pragmatics (problems interpreting the use of language in context and the non-literal use of language), and abnormal intonation and vocal quality. Although relatively little research to date has focused on the sign language deficits of deaf children with autism, in this chapter we will review what is currently known about the sign language of such children. It is worth noting from the outset that virtually all work on this population has occurred since 2010, and findings are still preliminary. Apparent dramatic increases in the rates of autism in the general popula- tion (1 in 88 children in the United States; Centers for Disease Control, 2012) 4 2639_Ch04.indd 90 2639_Ch04.indd 90 05-12-2013 18:40:26 05-12-2013 18:40:26