Expanding the gestural model of lexical tone: evidence from two dialects of Serbian

Featural and gestural models of tone differ on the degree to which they include timing information in the representation. However, both assume some kind of simultaneity between tones and their tone-bearing units, where featural models emphasize the role of acoustic relationships and gestural models instead emphasize articulatory coordination. We present the results of two acoustic production studies on two dialects of Serbian, a lexical pitch accent language. In the Belgrade dialect, pitch accents are aligned relatively late in the tone-bearing unit, while in the Valjevo dialect, pitch accents are phonetically retracted, sometimes into the preceding syllable. We varied the syllable onsets of tone-bearing units in falling (experiment 1) and rising (experiment 2) pitch accents, and measured the effects on F0 contours. Despite these differences in phonetic alignment, the phonological system is the same in both dialects. We argue that this apparent mismatch between the phonology and phonetics can be expressed straightforwardly in the Articulatory Phonology framework by allowing tone gestures to coordinate with other gestures in all the ways that segmental gestures can, rather than restricting tone to c-center coordination.

Rhotic Variation in Costa Rican Spanish

The class of sounds classified under the umbrella term “rhotic” demonstrate considerable variability across, languages, dialects, and speech styles. This is no exception in Spanish, where rhotics have received considerable attention. Among dialects of Spanish, the pronunciation of rhotics in Costa Rican Spanish is a highly salient feature of this variety, where the standard trill /r/ and tap /ɾ/ are often assibilated or realized as fricatives. A number of studies have examined Costa Rican rhotics from both phonological and phonetic perspectives, yet the results of these studies have been inconclusive. Notably absent from these studies are acoustic analyses of rhotic production, instead relying on impressionistic transcriptions which risk glossing over phonetic detail. This pilot study revisits the question of rhotic variation in Costa Rican Spanish by analyzing five sociolinguistic interviews with native speakers of Costa Rican Spanish. Using acoustic analyses of rhotic tokens, I propose a rhotic inventory for this variety which includes approximant and fricative variants in addition to the standard tap and trill. Additionally, I propose a potential explanation for the distribution of rhotic variants through an Articulatory Phonology framework, suggesting that rhotic variation can be explained as a result of gestural weakening and co-articulation. The study presents preliminary conclusions regarding socioeconomic factors, suggesting areas for future research, including the effect of age and gender on rhotic variation. Overall this work contributes to the understanding of the Costa Rican variety of Spanish, considering both linguistic and extralinguistic factors as potential predictors of variation.

Cracking Prosody in Articulatory Phonology

Articulatory Phonology advances an account of phonological structure in which dynamically defined vocal tract tasks—gestures—are simultaneously and isomorphically units of cognitive representation and units of physical action. This paradigm has fundamentally altered our understanding of the linguistic representation of words. This article reviews the relatively recent incorporation of prosody into Articulatory Phonology. A capsule review of the Articulatory Phonology theoretical framework is presented, and the notions of phrasal and prominence organization are introduced as the key aspects of linguistic prosodic structure under consideration. Parameter dynamics, activation dynamics, and prosodic modulation gestures, such as the π-gesture, are outlined. The review is extended to touch on rhythm, intonation, and pauses and to consider innovations for integrating multiple aspects of prosodic structure under this dynamical approach. Finally, a range of questions emerges, crystallizing outstanding issues ranging from the abstract and theoretical to the interactive and functional.

Expanding the gestural model of lexical tone: evidence from two dialects of Serbian

Featural and gestural models of tone differ on the degree to which they include timing information in the representation. However, both assume some kind of simultaneity between tones and their tone-bearing units, where featural models emphasize the role of acoustic relationships and gestural models instead emphasize articulatory coordination. We present the results of two acoustic production studies on two dialects of Serbian, a lexical pitch accent language. In the Belgrade dialect, pitch accents are aligned relatively late in the tone-bearing unit, while in the Valjevo dialect, pitch accents are phonetically retracted, sometimes into the preceding syllable. We varied the syllable onsets of tone-bearing units in falling (experiment 1) and rising (experiment 2) pitch accents, and measured the effects on F0 contours. Despite these differences in phonetic alignment, the phonological system is the same in both dialects. We argue that this apparent mismatch between the phonology and phonetics can be expressed straightforwardly in the Articulatory Phonology framework by allowing tone gestures to coordinate with other gestures in all the ways that segmental gestures can, rather than restricting tone to c-center coordination.

Data-Driven Critical Tract Variable Determination for European Portuguese

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.

Articulatory Phonology

One of the most fundamental problems in research on spoken language is to understand how the categorical, systemic knowledge that speakers have in the form of a phonological grammar maps onto the continuous, high-dimensional physical speech act that transmits the linguistic message. The invariant units of phonological analysis have no invariant analogue in the signal—any given phoneme can manifest itself in many possible variants, depending on context, speech rate, utterance position and the like, and the acoustic cues for a given phoneme are spread out over time across multiple linguistic units. Speakers and listeners are highly knowledgeable about the lawfully structured variation in the signal and they skillfully exploit articulatory and acoustic trading relations when speaking and perceiving. For the scientific description of spoken language understanding this association between abstract, discrete categories and continuous speech dynamics remains a formidable challenge. Articulatory Phonology and the associated Task Dynamic model present one particular proposal on how to step up to this challenge using the mathematics of dynamical systems with the central insight being that spoken language is fundamentally based on the production and perception of linguistically defined patterns of motion. In Articulatory Phonology, primitive units of phonological representation are called gestures. Gestures are defined based on linear second order differential equations, giving them inherent spatial and temporal specifications. Gestures control the vocal tract at a macroscopic level, harnessing the many degrees of freedom in the vocal tract into low-dimensional control units. Phonology, in this model, thus directly governs the spatial and temporal orchestration of vocal tract actions.

/dˤ/-Variation in Saudi Newscasting and Phonological Theory

In his analysis of /dˤ/-variation in Saudi Arabian newscasting, Al-Tamimi (2020) finds unpredicatble variability between the standard variant [dˤ] and the non-standard variant [ðˤ] in different in-words positions, in different phonetic environments, and in semantically ‘content’ and suprasegmentally ‘stressed’ lexical itmes assumed to favor the standard variant. He even finds in many of these lexical items an unusual realizational flucatuation between the two variants. The present exploratory and ‘theory-testing’ study aims to find a reasonable account for these findings through examining the explanatory adequacy of a number of available phonological theories, notions, models and proposals that have made different attempts to accommodate variation, and this includes Coexistent Phonemic Systems, Standard Generative Phonology, Lexical Diffusion, Variable Rules, Poly-Lectal Grammar, Articulatory Phonology, different versions of the Optimality Theory, in addition to the Multiple-Trace-Model, as represented by Al-Tamimi’s (2005) Multiple-Trace-Based Proposal. The study reveals the strengths and weaknesses of these theories in embracing the variability in the data, and concludes that the Multiple-Trace-Based Proposal can relatively offer the best insight as its allows variation to be directly encoded in the underlying representations of lexical items, a status strictly prohibited by the rest of the theories that adopt invariant lexical representations in consonance with the ‘Homogeneity Doctrine’.

Evidence motivating consideration of an alternative approach

This chapter begins to motivate the development of an alternative approach to speech production by pointing out three potential difficulties with the highly-successful Articulatory Phonology/Task Dynamics approach. First, it discusses the extensive nature of modifications to AP/TD default specifications required to account for the wide variety of surface phonetic forms. The need for a large number of adjustments in AP/TD raises questions about the appropriateness of the AP/TD default-adjustment approach, which would have been more appropriate if the default, non-prominent, phrase-medial, normal-speech-rate specifications could be used most of the time. Second, it discusses the lack of a principled explanation for behaviors described by Fitts’ law. While the theory can accommodate some aspects of Fitts’ law, others are not explained or accommodated. Finally, it suggests that AP/TD’s gestural score architecture raises the risk of spatial interference among overlapping, independent gestures. These three challenges taken together set the stage for the discussion of additional challenges in Chapter 4, which further motivate consideration of phonology-extrinsic-timing-based approaches to speech motor control.

Articulatory Phonology/Task Dynamics

This chapter summarizes the basic mechanisms of the Articulatory Phonology model, currently the most thoroughly worked-out model in the literature, with a focus on its system-intrinsic mechanisms used to account for systematic variation in speech timing. Key features of the model are reviewed, and oscillator-based mechanisms are described for timing control for articulatory gestures, control of inter-gestural coordination, prosodic timing control, and the control of overall speech rate. Strengths of the AP/TD approach are discussed, which include facts that are well-accounted-for within this model, such as the predominance of CV syllables within the world’s languages, as well as characteristics of processing within the model that are assumed to be advantageous, such as the avoidance of the need to explicitly plan the details of articulatory movement when planning an utterance. This presentation forms the basis of the evaluation presented in subsequent chapters.