期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：24
页码：11705-11711
DOI：10.1073/pnas.1819872116
出版社：The National Academy of Sciences of the United States of America
摘要：Logical properties such as negation, implication, and symmetry, despite the fact that they are foundational and threaded through the vocabulary and syntax of known natural languages, pose a special problem for language learning. Their meanings are much harder to identify and isolate in the child’s everyday interaction with referents in the world than concrete things (like spoons and horses) and happenings and acts (like running and jumping) that are much more easily identified, and thus more easily linked to their linguistic labels ( spoon , horse , run , jump ). Here we concentrate attention on the category of symmetry [a relation R is symmetrical if and only if (iff) for all x , y : if R ( x , y ), then R ( y , x )], expressed in English by such terms as similar , marry , cousin , and near . After a brief introduction to how symmetry is expressed in English and other well-studied languages, we discuss the appearance and maturation of this category in Nicaraguan Sign Language (NSL). NSL is an emerging language used as the primary, daily means of communication among a population of deaf individuals who could not acquire the surrounding spoken language because they could not hear it, and who were not exposed to a preexisting sign language because there was none available in their community. Remarkably, these individuals treat symmetry, in both semantic and syntactic regards, much as do learners exposed to a previously established language. These findings point to deep human biases in the structures underpinning and constituting human language.
关键词：language emergence ; sign language ; logical structure of language ; homesign ; symmetry
