Speaker: Rory Turnbull (University of Hawaii)
Title: Hidden structure in the phonological lexicon
Abstract: Various proposals have claimed that functional pressures may influence linguistic structure. These pressures include learning biases, phonetic constraints, and communicative imperatives. With regards to word similarity in the phonological lexicon, some potentially competing pressures can be identified: From the perspective of a language learner, phonological similarity among words is helpful, as commonly occurring sequences or elements can be re-used, allowing for quicker acquisition of articulatory scores. From the perspective of a language user, however, phonological dissimilarity is favored, as a phonologically disperse lexicon provides more redundancy and a more robust signal, allowing for ease of communication. We investigate whether such pressures have a measurable influence on the structure of the phonological lexicon. In this talk we present a novel approach to the study of the phonological lexicon via complex network modeling. This modeling relies on the notion that each word in the lexicon is connected to its nearest phonological neighbours. By connecting all words in this manner, the lexicon can be examined as a network of interconnected nodes, and the tools of complexity science can be applied. By comparing the lexicons of nineteen genetically and typologically dissimilar languages to over four thousand pseudo-lexicons randomly generated under controlled conditions, it is possible to determine the provenance of various features of lexical structure. We confirm that, in accordance with linguists' intuitions, phonotactics play an important role in determining the structure of lexicons. Above and beyond the effects of phonotactics, our results provide evidence of constraints operating over the lexicon, which are hypothesized to be of functional importance for language acquisition, production, and comprehension. Future work and extensions to other domains are discussed.