Nominal Coercion in Space: Mass/Count Nouns and Distributional Semantics
Authors: Manuela Hürlimann, Raffaella Bernardi, Denis Paperno (Università di Trento, 2014)
Topic: Lexical and Semantic Resources and Analysis

Abstract
Theoretical linguists analyse all nouns as either mass or count, but ad-mit that noun meanings can be shifted from one class to the other and classify these shifts. We use distributional seman-tic models to check how the theoretical analysis of mass-count meaning shifts re-lates to the actual usage of the nouns.

Introduction
It is generally assumed that if a mass (count) noun is used in a count (resp. mass) context, its meaning changes. Compare example (1), where wine is used in a mass context (as a bare singular; denoting a substance) to (2), where the use of the determiner three indicates a count usage, shifting its interpretation to types of wine. (1) I like wine. (2) Three wines grow in this region. The same phenomenon can also be observed for count nouns: in example (3), apple is used in its more frequent count sense, while its bare usage in example (4) constitutes a mass usage with a slightly changed meaning — the focus is not on individual, whole apples as in the countable example, but on their material/substance. (3) I bought five apples at the market. (4) There is apple in the salad. Data-based approaches to the mass/count phenomenon include Baldwin and Bond (2003), who classify nouns into five countability types based on lexico-syntactic features and Ryo Nagata et al. (2005), who use context words to distinguish between mass and count nouns. Katz and Zamparelli (2012) were the first to study mass/count elasticity using distributional semantic models. First of all, they dispelled the view that there is a clear count/mass dichotomy: like in the examples above, many nouns which appear frequently in count contexts also appear frequently in mass contexts. Hence, rather than making a binary distinction (count vs. mass nouns), we should speak of predominantly count (resp., predominantly mass) nouns, i.e., nouns which occur more frequently in count (resp. mass) contexts than in mass (resp., count) contexts. Moreover, Katz and Zamparelli (2012) take pluralisation as a proxy for count usage and conjecture that for predominantly count nouns the similarity between singular and plural is higher than for predominantly mass nouns since the latter undergo a shift whereas the former do not. This conjecture finds quantitative support in their data – the 2- billion word ukWaC corpus.1 We wonder whether other factors, such as polysemy, have an impact on this quantitative analysis and we further investigate nominal coercion by also considering the abstract vs. concrete dimension and polysemy. Katz and Zamparelli (2012) notice that while plurals are invariably count, singulars can be a mixture of mass and count usages, and propose to use syntactic contexts to disambiguate mass and count usages in future studies. We take up their suggestion and look at coercion using vector representations of mass vs. count usages. According to the linguistic literature (Pelletier (1975)), instances of coercion fall into several shift classes. In this view, coerced nouns move towards a particular “destination”: Container shift: Liquids (mass) are coerced into countable quantities contained in containers: “two beers, please!” Kind shift: Masses are coerced into a kind reading: “three wines grow in this region” Food shift: Animal nouns are coerced into a mass food meaning: “there was chicken in the salad” Universal grinder: Countables are coerced into a mass reading: “after the accident, there was dog all over the street” We wonder whether these shift classes can be identified in the semantic space. Thus, we propose a simple experiment in which we assess whether the count usage vectors of typical mass nouns move towards (=become more similar to) these suggested destinations. In sum, we address the following research questions: (1) Do nouns undergo noticeable shifts – and if so, what factors have an impact? (2) Can we interpret the destination of a shift in terms of standard shift classes?

Conclusion
We have seen how Distributional Semantics Models (DSMs) can be applied to investigate nominal coercion. DSMs can capture some aspects of mass/count noun meaning shifts, such as the fact that predominantly mass nouns undergo greater meaning shifts than predominantly count nouns when pluralised. We also find that abstractness and polysemy have an impact on singular-plural distance: abstract nouns and highly polysemous nouns have a greater singular-plural distance than concrete and monosemous nouns, respectively. Furthermore, our second experiment shows that coercion lies mainly in cases where both the mass and count usage vectors stay close to the averaged noun meaning. However, as our toy evaluation of clear cases of container and kind coercion shows, the direction of the shift can be differentiated based on usage vectors.