A replicable acoustic measure of lenition and the nature of variability in Gurindji stops

Abstract

An automated method is presented for the commensurable, reproducible measurement of duration and lenition of segment types ranging from fully occluded stops to highly lenited variants, in acoustic data. The method is motivated with respect to the relationship between acoustic and articulatory phonetics and, through subsequent evaluation, is argued to correspond well to articulation. It is then applied to the phonemic stops of casual speech in Gurindji (Pama-Nyungan, Australia) to investigate the nature of their articulatory targets. The degree of stop lenition is found to vary widely. Contrary to expectations, no evidence is found of a positive effect on lenition due to word-medial (relative to word-initial) position, beyond that attributable to duration; nor do non-coronals lenite more than their apical counterparts, which freely lenite along a continuum towards taps. No significant effect is found of preceding or following vocalic environment. Taken together, the observed lenition, duration, and peak intensity velocities are argued to be inconsistent with a single, fully-occluded articulatory 'stop' target which is undershot at short durations, rather targets can be understood to span a range or 'window' of values in the sense of Keating (1990), from fully-occluded stop-like targets to more approximantlike targets. It is an open question to what degree the patterns found in Gurindji are language particular, or can be related to the organization of obstruent systems in Australian languages more broadly. Precisely comparable studies of additional languages will be especially valuable in addressing these questions and others, and are possible using the method we introduce.

The phonetics and phonology of lenition: A Campidanese Sardinian case study

“…Although lenition patterns have been described in hundreds of languages (e.g., Kirchner, 1998;Lavoie, 2001), fundamental questions about the nature of these patterns are still a topic of debate in the phonetic and phonological literature. Several recent studies address the question of how best to describe, measure, and quantify lenition in phonetic terms (e.g., Kingston, 2008;Hualde, Simonet, & Nadeu, 2011;Warner & Tucker, 2011;Bouavichith & Davidson, 2013;Ennever, Meakins, & Round, 2017;Cohen Priva & Gleason, 2019). Understanding the functional nature of lenition and its place in phonological grammar requires that we first understand what lenition does to sounds; while there is broad agreement that lenition tends to shorten consonants and render them louder or more vowel-like, there is limited consensus on the most principled ways to measure these properties.…”

“…This paper explores consonant lenition in a corpus of field recordings of Campidanese (also called Campidanian) Sardinian, a language with complex lenition patterns that interact with voicing, manner, and length contrasts (Virdis, 1978;Bolognesi, 1998). We show that the duration and change-in-intensity algorithm devised by Ennever et al (2017) can be fruitfully extended to a different language and to a more heterogeneous corpus.…”

“…This means that raw intensity measurements may not be reliable for tracking linguistic properties. Researchers have proposed various ways to control for such factors: measurements of consonant intensity relative to other consonants in a recording session with the same underlying features (Cohen Priva & Gleason, 2019), relative to some part of a flanking vowel or transition (Warner & Tucker, 2011;Ennever et al, 2017), or measurements of intensity slope/velocity during the transitions to and from flanking vowels (Kingston, 2008;Hualde et al, 2011). These procedures, however, may introduce their own problems: Because some of them reflect the intensity of adjacent vowels, they may not reliably isolate consonantal lenition effects (Bouavichith & Davidson, 2013;Cohen Priva & Gleason, 2019).…”

“…The fact that lenited consonants have increased intensity and are more similar to surrounding vowels makes measuring duration especially difficult. Ennever et al (2017) give an insightful overview of this issue and some of the points here are drawn from that discussion.…”

“…One could imagine, for instance, that stop closure gestures will noticeably reduce the intensity of a preceding vowel relatively early in their trajectories, while approximant constriction gestures could take longer to exert a noticeable effect. For these reasons (as well as practical efficiency), Kingston (2008) and Ennever et al (2017) develop automated duration-measurement algorithms based on changes in intensity. Kingston's algorithm measures the interval from the greatest downward intensity slope (corresponding to consonantal constrictions) to the greatest upward slope (corresponding to the release of constrictions); Ennever et al (2017) use smoothing splines fit to intensity contours, and propose a threshold at a fraction of the slope extrema, meant to correspond more closely to articulatory landmarks in consonantal constriction gestures.…”