What conditions tone paradigms in Yukuna: Phonological and machine learning approaches

Magdalena Lemus-Serrano,Dan Dediu,Marc Allassonnière-Tang

doi:10.5334/gjgl.1276

Abstract

Yukuna is an understudied Arawak language of North-West Amazonia with a privative tonal system. In this system, roots are underlyingly specified for tone, whilst affixes are toneless. However, affixation interacts with tone, leading to many variations in surface tonal patterns. This paper puts forth a qualitative analysis of Yukuna’s tonal system, and provides data-driven evidence in favor of this analysis using machine learning methods. More precisely, we use decision trees and random forests to assess quantitatively the predictions of the phonological analysis. A manually annotated corpus of verbal paradigms was split into a training and a testing set. We trained the computational classifiers on the first and tested their predictions on the second. We found that they predict the majority of the patterns and support the qualitative analysis. Additionally, they suggest avenues for enhancing the phonological analysis, by providing a ranking of the variables that highlight statistical tendencies within tonal patterns. Besides its contribution to understanding tonal systems in general and of that of Yukuna in particular, our work also suggests that such machine learning approaches might become part of the complex theoretical and methodological toolkit needed for language description and linguistic theory development.

Highlights

Parana contrasts with the sharp decline in vitality of the language when speakers move to nearby towns and cities, where Spanish and Portuguese are the dominant languages
We note that the decision tree and random forests converged in terms of the selection of relevant variables for the prediction of tonal patterns
This paper combined qualitative and quantitative approaches to the description of the Yukuna word-prosodic system. In combining these two methods, this paper provides important new insights into the tonal system of the language, and contributes to our knowledge on the typology of tonal systems in Amazonia

Summary

Introduction

Parana contrasts with the sharp decline in vitality of the language when speakers move to nearby towns and cities, where Spanish and Portuguese are the dominant languages The nominative argument of verbs (S) is obligatorily encoded in finite clauses either with a bound person index on the verb, or by an overt NP placed immediately before the verb. The accusative argument of verbs (P) is neither obligatorily encoded, nor indexed on the verb. Non-verbal word classes can be used predicatively, in non-verbal clauses, with or without a copula (Schauer et al 2005; Lemus Serrano 2020). Studies differ in terms of their analysis of the phonological status of aspirated consonants, either as consonant sequences involving /h/ (Ramirez 2001: 356), or as phonemes (Lemus Serrano 2020: 6).

Objectives

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Discussion

Conclusion