Volume 32, Issue 1 - Special Issue: The Locus of Ambiguity and the Design of Language

Human language defines the most complex outcomes of evolution. The emergence of such an elaborated form of communication allowed humans to create extremely structured societies and manage symbols at different levels including, among others, semantics. All linguistic levels have to deal with an astronomic combinatorial potential that stems from the recursive nature of languages. This recursiveness is indeed a key defining trait. However, not all words are equally combined nor frequent. In breaking the symmetry between less and more often used and between less and more meaning-bearing units, universal scaling laws arise. Such laws, common to all human languages, appear on different stages from word inventories to networks of interacting words. Among these seemingly universal traits exhibited by language networks, ambiguity appears to be a specially relevant component. Ambiguity is avoided in most computational approaches to language processing, and yet it seems to be a crucial element of language architecture. Here we review the evidence both from language network architecture and from theoretical reasonings based on a least effort argument. Ambiguity is shown to play an essential role in providing a source of language efficiency, and is likely to be an inevitable byproduct of network growth.

The paper argues that syntax is motivated by the need to avoid combinatorial search in parsing and semantic ambiguity in interpretation. It reports on a case study for the emergence and sharing of first-order phrase structures in a population of agents playing language games. First-order phrase structures combine words into phrases but do not yet generalise to hierarchical or recursive phrases. To study why human languages exhibit phrase structure, a series of strategies for creating and sharing linguistic conventions are examined, starting from a lexical strategy without syntax and then studying the use of groups, n-grams and patterns. Each time we show in which way a strategy improves on the computational complexity of the previous on.

In this paper we focus on the topic of ambiguity resolution in and beyond grammar. We deal with two questions: where is ambiguity resolved (in particular, the ambiguity of expressions conveying specific forms of information packaging and common ground management), and what is the design of grammar that emerges from the study of ambiguity problems. After a review of the standard analysis of ambiguity within the Principles and Parameters model, in which ambiguous syntactic objects require different structures at syntax, we will focus on various phenomena that will support a model of grammar in which syntactic structures are mapped into information structures, which will feed both logical form and PF interfaces. In particular, we will show that scope relations between numeral quantifiers in Catalan and the interpretation of preverbal bare nominals in Brazilian Portuguese are sensitive to information structures that need to be translated into representations of meaning which are different from classical LFs in generative grammar. Only PFs are ambiguous.

We give a type logical categorial grammar for the syntax and semantics of Montague's seminal fragment, which includes ambiguities of quantification and intensionality and their interactions, and we present the analyses assigned by a parser/theorem prover CatLog to the examples in the first half of Chapter 7 of the classic text Introduction to Montague Semantics of Dowty, Wall and Peters (1981).

In this paper we investigate the role of prosody and gesture in the interpretation of yes -answers to negative yes/no -questions in Catalan, a language with a polarity-based system of confirmation/contradiction of negative yes/no -questions. Two rating experiments were conducted to test (i) whether yes answers to negative yes/no -questions are perceived as ambiguous by Catalan speakers when prosody and gesture are not available (Experiment 1), and (ii) whether the interpretation of sí ‘yes’ as an answer to a negative yes/no -question is dependent on prosodic and gestural properties of the answer (Experiment 2). Our results show that yes always asserts a salient propositional discourse referent, which can be either p or ¬ p . Intonation and gesture guide the interpretation of yes answers to negative yes/no -questions in Catalan, and we show that a yes answer with a marked intonation and gesture is to be interpreted as a denial or REJECT of a salient propositional discourse referent.

Natural languages come in two different modalities – the aural-auditory modality of spoken languages and the visual-gestural modality of sign languages. The impact of modality on the grammatical system has been discussed at great length in the last 20 years. By contrast, the impact of modality on semantics in general and on ambiguities in particular has not yet been addressed in detail. In this paper, we deal with different types of ambiguities in sign languages. We discuss typical lexical and structural ambiguities as well as modality-specific aspects such as ambiguities in the use of the signing space and non-manual markers. In addition, we address the questions how sign languages avoid ambiguities and to what extent certain kinds of ambiguities and non-ambiguities depend on the visual-manual modality of sign languages. Since gestures use the same articulatory channel that is also active in the production of signs, we also discuss ambiguities between gestures on the one hand and grammaticalized gestures and signs on the other.