Predicting native speaker choice: the role of corpus-based frequency metrics in morpho-syntactic alternations

Abstract This paper investigates the role of corpus-based frequency metrics in predicting native speaker choice in Estonian, a Finno-Ugric language with rich inflectional morphology. We test whether frequency affects the choice between two constructions which represent the alternants of a morphosyntactic alternation in Estonian – the adessive case construction and the postpositional peal construction. Both constructions are used, inter alia , to express the spatial relationship of one object located on top of another object, e.g. Raamat on laual/laua peal ‘The book is on the table’. We further compare which out of several well-established frequency metrics yields the most accurate predictions and whether frequency on its own outperforms the predictiveness of significant semantic and morpho-syntactic variables identified in previous research (e.g. Klavan, Jane. 2012. Evidence in linguistics: Corpus-linguistic and experimental methods for studying grammatical synonymy (Dissertationes Linguisticae Universitatis Tartuensis). Tartu: University of Tartu Press, Klavan, Jane. 2020. Pitting corpus-based classification models against each other: A case study for predicting constructional choice in written Estonian. Corpus Linguistics and Linguistic Theory 16(2). 363–391). The comparison of several mixed-effects logistic regression models showed that out of seven frequency metrics considered overall, only those related to the postposition peal are predictive. Adding previously established semantic and morphosyntatic variables to the winning frequency metrics significantly improved model fit and outperformed any simpler model. We conclude that frequency affects the choice between two constructions in different ways and that it does not explain away other functional predictors.