Minimizing dependencies across languages and speakers. Evidence from basque, polish and spanish and native and non-native bilinguals.

Abstract

Within the last years, evidence for a general preference towards grammars reducing the linear distance between elements in a dependency has been accumulating (e. g., Futrell, Mahowald, and Gibson, 2015b; Gildea and Temperley, 2010). This cognitive bias towards dependency length minimization has been argued to result from communicative and cognitive pressures at play during language production. Although corpus evidence supporting this claim is quite broad insofar as grammaticalized structures are concerned (e. g., Futrell et al., 2015b; Liu, 2008; Temperley, 2007, among others), its validity rests on more shaky foundations regarding production preferences (Stallings, MacDonald, and O¿Seaghdha, 1998; Wasow, 1997; Yamashita and Chang, 2001, among others). This dissertation intends to address this gap. It examines whether dependency length minimization is an active mechanism shaping language production preferences, and explores the specific nature of this principle and its interplay with linguistic specifications and architectural properties of the human memory system. In a series of 5 cued-recall production experiments and 2 complex memory span tasks, I investigate the effect of dependency length in modulating production preferences across languages with differing grammatical properties (e.g., head-position and case marking) and across speakers (e. g., natives and non-natives and with variable working memory capacity). I begin by showing that the preference for short dependencies is better accounted by a general cognitive preference for minimizing the distance across dependents than by conceptual availability. I then show how languages as diverse as Basque, Spanish and Polish tend to choose the communicatively more efficient structures, when there is more than one available alternative to express the same meaning. Crucially, I confirm that there is consistent variation regarding this tendency both across languages and across speakers. I argue that language-specific (e. g., pluripersonal agreement) and general cognitive mechanisms (e. g., word order based-expectations) interact with the preference towards dependency length minimization. Also, I show that the degree of communicative efficiency achieved by highly proficient and early non-native bilingual speakers is lower than that reached by their native peers. Finally, I find that the bias towards shifted orders that yield shorter dependencies correlates positively with working memory. Based on these findings, I conclude that there is strong evidence supporting the claim that dependency length minimization is a pervasive force in human language production, resulting from a general cognitive constraint towards efficient communication, and also that its strength varies depending on grammatical and individual specifications compatible with information-theoretic considerations.