International Day of Sign Languages

  One of the fundamental properties of human language is that it can be used to create an unlimited number of utterances given a limited number of pieces. At the syntactic level, this property follows directly from a mathematical property of language called recursiveness. We’re all familiar with recursiveness (even if not with the term). It is found in language , and computer programs, and even in children’s stories, as in (1). In (1), the process or rule that creates a relative clause (here, the clauses beginning with that) has applied repeatedly to the noun phrases inside other relative clauses. This repeated application of the same rule to create more and more complex sentences is an example of recursiveness. The children’s story is amusing precisely because we all know that there is no theoretical limit to the application of this rule. Any speaker of English can add to the story by generating another relative clause at the beginning, as in (2). The only limitations on th...

  The discovery of these sign language properties brings to light observations about spoken language that seem to be determined by the modality alone, such as the tendency to string linguistic information out linearly, and the generally arbitrary nature of the lexicon and grammar. Before research on sign language, such characteristics were thought to be properties of language universally.  In the light of sign language research, we may suggest that these properties are artefacts of the oral–aural modality. Our work is cut out for us. An important goal of future research must be to develop models of language that explain the clustering of characteristics found in sign languages , as well as the fact that they conform to more general linguistic universals . In developing such models, we are charged with an equally important task: explaining precisely what it is about the spoken language modality that makes it different from sign language. Only by examining these two natural ...