Language, Cognition, and the Brain: Insights from Sign Langauge Research (review)

THIS BOOK PRESENTS an up-to-date summary, discussion, and analysis of research on the representation of language in the human brain, with special attention to the representation of signed language, most especially American Sign Language as used by deaf signers. Emmorey, one of the leading researchers in this area, sets out to examine the extent to which neurolinguistic research on sign language users can shed light on several questions at the heart of recent controversy in the study of language. She succeeds admirably in presenting, synthesizing, and interpreting a large and complex body of information in a format that will make this information widely accessible.

A brief review of the chapter topics gives a sense of the scope of the book. Chapter 1, the introduction, presents information on the development of Nicaraguan Sign Language, to illustrate the processes through which signed languages develop, and it also debunks some of the popular misconceptions about these languages. Chapter 2, "The Structure of American Sign Language: Linguistic Universals and Modality Effects," reviews sign language phonology and syntax, pointing out similarities, but also differences, in organization, having to do with the use of space in signed languages (SLs). The ramifications of the use of space in SLs and what it can reveal about the universal neurological underpinnings of language in general is the focus of the remainder of the book, which is divided into seven additional chapters, dealing with the following topics: language and space, psycholinguistics of sign perception and production, sign language acquisition, the critical-period hypothesis, memory for sign language, the impact of sign language use on visuospatial cognition, and sign language and the brain.

This book will be challenging for nonspecialists, but summaries at the ends of the chapters may prove useful even if some details of the technical research are beyond the reach of the reader—the reader will be getting high-level summaries of findings and interpretation from a major practitioner in this field. Many will find that the reference list alone is a major resource. The remainder of this review focuses on three aspects of signing in which the similarities and differences with speech are especially revealing—the analogous use of space through classifier constructions, the acquisition of language by children, and hemispheric representation in the brain.

The pivotal chapter is the third, "The Confluence of Language and Space." According to Emmorey,

Classifier constructions are the primary linguistic structure used to express both concrete and abstract concepts of motion and location. ASL signers also exploit signing space to schematically represent spatial relations, time, and aspects of conceptual structure. When signers describe spatial relations, there is a structural analogy between the form of a classifier construction and aspects of the described scene. (115)

In other words, the nature of the structural relationship between the form of the signed utterance and the described scene is generally iconic (either directly or by metaphoric extension). The idea that ASL grammar is at least partly analog is not new (e.g., DeMatteo 1977), and it has been hotly contested. What is now possible, and what Emmorey does, is to give us a comprehensive account of the interplay of analog and digital processes in ASL and the consequences of this complexity for both language acquisition by children and the consequent representation of these processes in the brain.

In fact, what Emmorey makes clear is that, far from marking ASL as simpler or more primitive than speech, an old prejudice, analog processes such as classifier constructions may be extremely complex and difficult to acquire:

In sum, children do not acquire the ASL classifier system easily or without error, despite the clear iconicity of the system. At the youngest ages (2;0 to 3;0), children are able to produce handling classifier handshapes and use whole entity classifier handshapes to designate a moving figure object. However, the...