Semantic structures, communicative strategies and the emergence of language

My thesis studies communication systems that arise in the absence of linguistic conventions: restricted linguistic systems. Home sign and the language of unsupervised adult second language learners are examples of such systems. Jackendoff (2002) observed that utterances in these systems are governed by semantic principles, such as Agent First (a principle responsible for the intuitive difference between the two simple utterances HIT-TREE-FRED and HIT-FRED-TREE), and argued that they reflect ancient linguistic structures. As such, studying restricted linguistic systems offers a window into the earliest stages of language evolution, as well as offering insights into the cognitive biases which act to shape modern linguistic systems. In my thesis I related restricted linguistic systems to a novel experimental approach, improvised communication. I showed that gesture sequences in the improvised communication experiment are governed by semantic principles which are essentially the same as those governing restricted linguistic systems: we can therefore use improvised communication experiments as a source of evidence for semantic principles in evolutionarily early language. Moreover, I used improvised communication experiments to reveal a new semantic ordering principle governing the expression of intensional meaning. In an improvised communication experiment, participants are asked to describe events using only gesture and no speech. The methodology was first presented by Goldin-Meadow et al. (2008), who showed that participants by-pass the grammar rules of their native language and use a gesture order that is consistent with SOV (i.e. Subject-Object-Verb). Goldin-Meadow et al. conclude that this is the order in which we naturally represent events. In one study I contrasted extensional (e.g., ‘Man kicks ball’) and intensional (e.g., ‘Man searches for ball’) events. These two kinds of events differ semantically (e.g., ‘ball’ is a concrete object when it is an argument of ‘kick’, and an abstract object when it is an argument of ‘search for’), and participants use different orders to communicate about them: they consistently use SOV order for extensional and SVO order for intensional events. In a follow-up study I show that this flexibility in word order has a communicative function: ambiguous SOV gesture sequences are interpreted extensionally, while ambiguous SVO sequences are interpreted intensionally. These findings suggest added subtlety to the Goldin Meadow account: word order in improvised communication is flexible and determined by fine-grained properties of the meaning to be conveyed

An evolutionary approach to sign language emergence:From state to process

Understanding the relationship between gesture, sign, and speech offers a valuable tool for investigating how language emerges from a nonlinguistic state. We propose that the focus on linguistic status is problematic, and a shift to focus on the processes that shape these systems serves to explain the relationship between them and contributes to the central question of how language evolves

Investigating word order emergence:Constraints from cognition and communication

How do cognitive biases and mechanisms from learning and use interact when a system of language conventions emerges? We investigate this question by focusing on how transitive events are conveyed in silent gesture production and interaction. Silent gesture experiments (in which participants improvise to use gesture but no speech) have been used to investigate cognitive biases that shape utterances produced in the absence of a conventional language system. In this mode of communication, participants do not follow the dominant order of their native language (e.g., Subject-Verb-Object), and instead condition the structure on the semantic properties of the events they are conveying. An important source of variability in structure in silent gesture is the property of reversibility. Reversible events typically have two animate participants whose roles can be reversed (girl kicks boy). Without a syntactic/conventional means of conveying who does what to whom, there is inherent unclarity about the agent and patient roles in the event (by contrast, this is less pressing for non-reversible events like girl kicks ball). In experiment 1 we test a novel, fine-grained analysis of reversibility. Presenting a silent gesture production experiment, we show that the variability in word order depends on two factors (properties of the verb and properties of the direct object) that together determine how reversible an event is. We relate our experimental results to principles from information theory, showing that our data support the “noisy channel” account of constituent order. In experiment 2, we focus on the influence of interaction on word order variability for reversible and non-reversible events. We show that when participants use silent gesture for communicative interaction, they become more consistent in their usage of word order over time, however, this pattern less pronounced for events that are classified as strongly non-reversible. We conclude that full consistency in word order is theoretically a good strategy, but word order use in practice is a more complex phenomenon