The aerodynamics of voiced stop closures

Luis M T Jesus,Maria Conceição Costa

doi:10.1186/s13636-019-0162-z

Luis M T Jesus, Maria Conceição Costa

Open Access

https://doi.org/10.1186/s13636-019-0162-z

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Abstract

Experimental data combining complementary measures based on the oral airflow signal is presented in this paper, exploring the view that European Portuguese voiced stops are produced in a similar fashion to Germanic languages. Four Portuguese speakers were recorded producing a corpus of nine isolated words with /b, d, ɡ/ in initial, medial and final word position, and the same nine words embedded in 39 different sentences. Slope of the stop release (SLP), voice onset time (VOT), release and stop durations and steady-state oral airflow amplitude characteristics preceding and following the stop were analysed. Differences between independent groups (three different places of articulation and two vowel contexts) and correlations between variables were studied; generalised linear mixed effects models were developed to study the effects of VOT, SLP and the factors place of articulation and vowel context on the mean oral airflow. A classification of stop’s voicing was automatically extracted. Both SLP (p = .013) and VOT (p = .014) were significantly different for the three places of articulation. Weak voicing was observed for 57% of the stops. It is hypothesised that the high percentages of weakly voiced stops are a consequence of passive voicing and that the feature of contrast in Portuguese is privative [spread glottis].

Highlights

The concept of contrast in the phonology of a language is closely linked to the competence of being able to isolate meaningful units such as phonemes or words
Speakers were asked to seat on a chair and read 48 prompts, displayed randomly on a sheet of paper held on a musical stand, which was placed in front of them, with normal effort and as close as possible to their natural speech: nine isolated words contained the European Portuguese (EP) voiced stops /b, d, ɡ/ in word-initial, word-medial and wordfinal positions; the same nine words were embedded in 39 different carrier sentences of the form:
This view is founded in previous acoustic waveform and spectrographic data shown in Fig. 8, where one can observe in what ways Portuguese voiced stops resemble those found in several Germanic languages [40]

Summary

Introduction

The concept of contrast in the phonology of a language is closely linked to the competence of being able to isolate meaningful units such as phonemes or words. The phonological laryngeal/voicing contrast is cued by a number of different features [13]: vocal fold vibration, duration of the adjacent phonemes and voice onset time (VOT) are just some of them. The theoretical framework of this study is grounded on views of the laryngeal feature of contrast for stops that have been considerably enriched over the last decade by new acoustic and articulatory phonetics evidence which strengthened arguments that in some languages, stop voicing is phonologically active and in others, it is passive [6]. A clear relation between phonetic cues and phonological processes that support this has yet to be found, so studies such as ours, based on new aerodynamic data that is more closely related to laryngeal behaviour, could contribute towards clarifying these issues. Velar stops from five out of six speakers were least likely to be produced with voicing during closure in low vowel context [40]

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