Introduction: Interface Asymmetries

The articles assembled in this issue of the Canadian Journal of Linguistics/Revue canadienne de linguistique contribute to our understanding of the role of asymmetric relations at the interfaces. Asymmetric relations have privileged status in the syntactic, phonological, and morphological derivation of linguistic expressions (see for example the articles in Di Sciullo 2003).

Interfaces are representations that mustmeet legibility conditions imposed by external systems. According to the Strong Minimalist Thesis (Chomsky 2001), language is an optimal solution to interface conditions, in that language is an optimal way to link sound and meaning. Questions arise regarding the properties of the interface representations that make them optimally legible by external systems. These properties could very well be abstract, and remote from the perceptual systems, and could bear on the form of interface representations, rather than on the interpretation of their parts. A strong hypothesis in this regard is that asymmetric relations are core properties of the relations derived by the grammar (Chomsky 1981, 1995, 2001; Kayne 1994; Moro 2000; Di Sciullo 2005; Zwart 2006). From this perspective, asymmetry is a pervasive property of derivations and interface representations; it is thus expected to be a property of different structural relations, such as the relation between a displaced constituent and its copy, the relation between an anaphor and its antecedent, the relation between a head and its dependent, and more generally, the relation between the constituents of a configuration.

Understanding of interface asymmetries is of central importance in generative grammar, since the asymmetries concern the mapping between the form and interpretation of linguistic expressions. Interfaces can be thought of as being representations ensuring the contact between different systems. Within the Minimalist Program (Chomsky 1995, and related work), interfaces are structural descriptions providing the necessary and sufficient information to be interpreted by the external systems, namely the conceptual-intentional and the sensorimotor systems.

Asymmetric relations can be thought of as unidirectional relations between two elements belonging to the same representation. Precedence, dominance, and sister-containment (asymmetric c-command) are themost discussed asymmetrical relations. Investigating interface asymmetries makes it possible to contribute to our understanding of core properties of the faculty of language, which is a part of the human genetic endowment. It might be the case that asymmetric relations are specific to the faculty of language, and contribute to differentiate the latter from the other faculties of the cognitive system.

We would expect asymmetric relations to play a crucial role at the interfaces, since this would restrict the class of relations optimally interpretable by external systems. Interface asymmetries would optimize the legibility of linguistic expressions, as they would reduce to one the set of properties of relations optimally legible by the external systems. Complexity would arise if, say, symmetry and asymmetry could equally contribute to interface legibility. Moreover, it is likely that the stability brought about by asymmetric relations as opposed to the instability brought about by symmetric relations would contribute to make interfaces optimally legible by external systems.

The advent of the Minimalist Program led to the adoption of a multiple spell-out derivationalmodel based on the unit of the phase. In this framework, legibility conditions are what make grammars usable by the performance systems. If asymmetry does make such a contribution, we would expect it to play a crucial role in the proper interpretation of different structural relations, including movement chains and head dependencies, as well as for linearization and parametric variation, and the contact between syntactic and prosodic phases.

The articles assembled in this special issue illustrate how the asymmetrical properties of movement, headedness, and structure contribute to the legibility of the interface representations by external systems, and thus contribute to the optimality of language design, efficiently linking sound and meaning. The issue is organized into three sections. The first is dedicated to the interface effects of asymmetric movement. The second section includes articles on headedness as an asymmetrical interface relation. And the articles in the last section present cases where asymmetric relations play a role in the derivation of covert structures, and structures that are parasitic to the syntactic hierarchy.

In the section on Movement, Ambar's article shows that asymmetric...