Data-Driven Critical Tract Variable Determination for European Portuguese

Samuel Silva,Nuno Almeida,Jens Frahm,António Teixeira,Arun Joseph,Conceição Cunha

doi:10.3390/info11100491

Abstract

Technologies, such as real-time magnetic resonance (RT-MRI), can provide valuable information to evolve our understanding of the static and dynamic aspects of speech by contributing to the determination of which articulators are essential (critical) in producing specific sounds and how (gestures). While a visual analysis and comparison of imaging data or vocal tract profiles can already provide relevant findings, the sheer amount of available data demands and can strongly profit from unsupervised data-driven approaches. Recent work, in this regard, has asserted the possibility of determining critical articulators from RT-MRI data by considering a representation of vocal tract configurations based on landmarks placed on the tongue, lips, and velum, yielding meaningful results for European Portuguese (EP). Advancing this previous work to obtain a characterization of EP sounds grounded on Articulatory Phonology, important to explore critical gestures and advance, for example, articulatory speech synthesis, entails the consideration of a novel set of tract variables. To this end, this article explores critical variable determination considering a vocal tract representation aligned with Articulatory Phonology and the Task Dynamics framework. The overall results, obtained considering data for three EP speakers, show the applicability of this approach and are consistent with existing descriptions of EP sounds.

Highlights

IntroductionMajor advances on phonetic sciences in the last decades contributed to better description of the variety of speech sounds in the world languages, to the expansion of new methodologies to less common languages and varieties contributing to a better understanding of spoken language in general.Speech sounds are not sequential nor isolated, but sequences of consonants and vowels are produced in a temporally overlapping way with coarticulatory differences in timing being language specific and varying according to syllable type (simplex, complex), syllable position (Marin and Pouplier [1]for timing in English, Cunha [2,3] for European Portuguese), and many other factors
Major advances on phonetic sciences in the last decades contributed to better description of the variety of speech sounds in the world languages, to the expansion of new methodologies to less common languages and varieties contributing to a better understanding of spoken language in general.Speech sounds are not sequential nor isolated, but sequences of consonants and vowels are produced in a temporally overlapping way with coarticulatory differences in timing being language specific and varying according to syllable type, syllable position (Marin and Pouplier [1]for timing in English, Cunha [2,3] for European Portuguese), and many other factors
After magnetic resonance imaging (MRI) acquisition and audio annotation, the data is uploaded to our speech studies platform, under development [35], and its processing and analysis are carried out resulting in a list of critical tract variables per phone

Summary

Introduction

Major advances on phonetic sciences in the last decades contributed to better description of the variety of speech sounds in the world languages, to the expansion of new methodologies to less common languages and varieties contributing to a better understanding of spoken language in general.Speech sounds are not sequential nor isolated, but sequences of consonants and vowels are produced in a temporally overlapping way with coarticulatory differences in timing being language specific and varying according to syllable type (simplex, complex), syllable position (Marin and Pouplier [1]for timing in English, Cunha [2,3] for European Portuguese), and many other factors. Speech sounds are not static target configurations clearly defined, their production involves complex tempo-spatial trajectories in the vocal tract articulators responsible for their production from the start of the movement till the release and back (e.g., in bilabial /p/ both lips move until the closure that produces the bilabial and the lips open again). All this movement is a so called articulatory gesture. It is important to differentiate between the actively activated (critical) articulators and the less activated or passive ones: For example, in the production of alveolar sounds as

Methods

Results

Discussion

Conclusion