2Chapter 0 Grammatical-Specic Language Impairment: A Window Onto Domain Specicity
There has been much debate as to which aspects of language are specic to language rather than shared with other aspects of cognition, and which aspects of language are specic to humans rather than shared with other groups of animals (Hauser, 2001; Hauser, Chomsky, & Fitch, 2002; Pinker & Jackendoff, 2005). In addition, there continues to be much discussion about how this specialized language system is represented and develops in the brain. New insight into this debate comes from studying people with a developmental language disorder, Specic Language Impairment (SLI), and particularly a subtype of this disorder known as Grammatical (G)-SLI. Such insight is bidirectional: our growing understanding of language and brain-systems enhances and directs our line of enquiry into SLI, furthering our knowledge of the underlying nature of both typical and atypical language development. In turn, this informs our enquiries about language and brain systems.