ANU-CoEDL ZOOM Seminar: Structural correlates of morphological redundancy, Matthew Carroll, 26 June
Seminar: Structural correlates of morphological redundancy: Toward an evolutionary explanation for stable inflectional overlap
Speaker: Matthew Carroll, Australian National University
When: 26 June 2020, 3pm
Where: via zoom (please email CoEDL@anu.edu.au for zoom link invitation)
Morphological redundancy is the phenomena where two or more co-occurring morphological formatives overlap in function. The most common examples of this are known as multiple or extended exponence but this also includes overlapping exponence, distributed exponence and a range of related well-attested phenomena. These phenomena pose a problem for an evolutionary theory of language change which predicts that redundancy should not be stable over time without additional selective pressure; yet, the psycholinguistic literature has yet to show any memory or processing benefits. One promising lead comes from genetic modelling, which has shown that genetic redundancy may be evolutionarily stable if one of the overlapping genes has both a lower efficacy and a lower mutation rate than the other. In this paper, we explore the inflectional systems of two unrelated language families known for their complex distribution of TAM marking, Yam and Kartvelian. By using an information theoretic notion of efficacy and estimating rates of change using shared forms and tree distance, we show a significant negative correlation in line with the models from genetics in both families. We view this as preliminary evidence in support of a structural explanation of inflectional redundancy based in the evolutionary dynamics of systems.