Sign eloquence beyond words

Forty years ago researchers began to claim that American Sign Language (ASL) had structure at both the sentence level and the word level, as is characteristic of natural human languages, and thus, should not be considered merely a primitive collection of mimetic gestures. The idea was controversial. The naturally developed signed languages of the deaf have also been confused with the invented signed systems used to represent English or other spoken languages. But within the current field of linguistics, the study of natural sign languages is recognised as a valid enterprise, and has developed into a sub-field marked by the same kinds of theoretical contributions and disputes as the detailed examination of other less commonly studied languages.

This book exemplifies linguistic arguments over analyses of syntactic constructions and their contributions to the development of theory. Although linguists recognise ASL as a language in the technical sense, there is much debate about the extent to which the rules or principles needed to explain ASL may differ from those needed for spoken languages. The authors make the claim that "despite some interesting modality-specific differences, signed languages are organised according to the same fundamental principles as spoken languages". They sometimes resort to novel interpretations of existing proposals, or take positions that are uncommon to account for the facts; while they criticise other researchers' technical innovations as unorthodox.

The bigger issue is whether the existing framework of a linguistic theory can be used to account for sign language, or whether completely new systems must be acknowledged. The book makes the case that generative syntax can do the job for a large component of the grammar. Unfortunately, the hardest potential problems for the theory are not addressed.

The book is unusual within generative syntax for including a chapter on "Methodological considerations". Sign languages are harder to study, because a large number of their users did not acquire the language from their parents, and even those from a long line of deaf signers must communicate regularly with non-native users. This may affect the data collected by researchers - and even perhaps the language itself. Researchers must be sensitive to the sociolinguistic situation in which ASL is found, and must be trained; native signer linguists are the ideal researchers. However, the authors' dismissal of the data of others goes too far, and may well mean that real variation in the language is inappropriately overlooked in their own work.

The analyses of the book are organised around the claim that many non-manual markers (facial expressions and body movements) express abstract syntactic features and reveal the hierarchical structure of the language. While the important role of many non-manual markers had been previously noted in the literature, the book includes claims of new non-manual grammatical markers, and a strong proposal about the relationship between non-manuals and syntactic structure. These theses should be tested.

Diane Lillo-Martin is professor of linguistics, University of Connecticut, United States.