New perspectives on duality of patterning: Introduction to the special issue.

Abstract

This special issue assembles a number of papers that present recent work on the nature and the emergence of duality of patterning. Duality of patterning (Hockett 1960) is the property of human language that enables combinatorial structure on two distinct levels: meaningless sounds can be combined into meaningful morphemes and words, which themselves could be combined further. We will refer to recombination at the first level as combinatorial structure, while recombination at the second level will be called compositional structure. According to Hockett (1960), duality of patterning is a design feature of human language (meaning that all human languages have it) while it is also unique to human language. He argued that it evolves when a growing number of meanings need to be expressed, so that combinatorial structure helps to keep signals distinct. More recently similar arguments have been made on the basis of mathematical and computational models (e. g. Nowak et al. 1999; Zuidema and de Boer 2009). Although it seems to be uncontroversial that recombination of meaningful elements (i.e. compositional structure) is needed for an unlimited system, the relation between an unlimited set of signals and recombination of meaningless elements (i.e. combinatorial structure) is less clear. 1.1 Is duality of patterning a design feature? On the one hand, simple combinatorial structure has been found in vocalizations of adult male putty-nosed monkeys with a relatively limited set of signals (Arnold and Zuberbuhler 2006; Yip 2006), indicating that duality may not be uniquely human and that it may occur in systems in which it is not needed to keep signals distinct. On the other hand, there is some evidence that duality of patterning is not required for a human language. Combinatorial structure does not appear to have crystallized in a recently emerging sign language: Al-Sayyid Bedouin Sign Language even though it is a fully expressive language (Sandler et al. 2011). In the ~75 years since its emergence, Al Sayyid Bedouin Sign Language (ABSL) has come to serve all the communicative functions usually associated with language and has been shown to have compositional structure at the levels of morphology (Meir et al. 2010) and syntax (Sandler et al. 2005; Padden et al. 2010). However, the community has not yet converged on a conventionalized level of meaningless elements, although the beginnings of phonology can be discerned (Sandler et al. 2011). The ABSL findings show that a language without a clearly phonological level of structure is possible. This contrasts with more established sign languages, whose lexical signs are made up of meaningless contrastive units belonging to the categories of handshape, location, and movement.1 While there is a degree of linear organization in the combination of elements in a sign, certain key formational elements combine with one another simultaneously and, as a result, a likely holistic source is often quite transparent. Because sign languages have a strongly iconic base, so that language users needn’t distinguish large sets of purely arbitrary holistic auditory signals, the ABSL researchers suggest that the development of a large vocabulary before holistic gestures are decomposed into a system of meaningless elements might be easier in signed than in spoken languages. However, as Blevins (2012) shows using data from spoken languages, iconicity is not a necessary condition for isomorphism between the two levels of structure to occur frequently in a language, and explanation of the evolution and predominance of dual patterning remains a challenge. We see then from the case of ABSL that the need to express a large set of signals does not necessarily lead to combinatorial structure, while conversely from the animal systems, it appears that combinatorial structure does not necessarily need a very large set of signals to emerge. As combinatorial structure is the main defining characteristic of duality of patterning, it appears that both the status of duality of patterning as a design feature of language and the evolutionary pathways leading to it need to be rethought.