In this paper, we discuss the implications for theories of the count/mass distinction that can be derived from the development of a large lexicon of English count and mass noun sense pairs, the Bochum English Countability Lexicon (BECL). The development of a lexicon for count and mass senses makes it possible that research on the count/mass distinction moves away from individual nouns and takes lexical variation into account. We focus on different types of ambiguity. The most important finding is that English shows a rather small class of nouns which are truly ambiguous with regard to the count/mass distinction, but not in any other respect. We suggest that these nouns show how the count/mass distinction is introduced into a language (which rests on the plausible assumption that all nouns begin their lives as mass nouns). The addition of denotational structure to provide individuation leads to an eventual petrification, which accounts for the somewhat surprising fact that there are many more count than mass nouns.

This paper provides a corpus-driven investigation into establishing classes of nouns based on grammatical environments relevant to countability, such as combination with cardinal modifiers or appearing as a bare singular. We investigate the countability environments of Allan (1980) and assess their predictive power across a large corpus (350 million words). We show, by applying machine learning methods, that while the environments Allan (1980) distinguishes are predictive, the occurrence of nouns as bare singular and/or bare plural is substantially more powerful as a diagnostic. Using the most important environments, we induce, through automatic clustering, a set of countability classses, which distinguish between varieties of countable, non-countable and pluralia tantum nouns.