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Spatiotemporal coordination in word-medial stop-lateral and s-stop clusters of American English
(2021)
This paper is concerned with the relation between syllabic organization and intersegmental spatiotemporal coordination using Electromagnetic Articulometry recordings from seven speakers of American English (henceforth, English). Whereas previous work on English has focused on word-initial clusters (preceding a vowel whose identity was not systematically varied), the present work examined word-medial clusters /pl, kl, sp, sk/ in the context of three different vowel heights (high, mid, low). Our results provide evidence for a global organization for the segments involved in these cluster-vowel combinations. This is reflected in a number of ways: compression of the prevocalic consonant and reduction of CV timing in the word-medial cluster case compared to its singleton paired word in both stop-lateral and s-stop clusters, early vowel initiation (as permitted by the clusters' phonetic properties), and presence of compensatory relations between phonetic properties of different segments or intersegmental transitions within each cluster. In other words, we find that the global organization presiding over the segments partaking in these word-medial tautosyllabic CCVs is pleiotropic, that is, simultaneously expressed in multiple phonetic exponents rather than via a privileged metric such as c-center stability or any other such given single measure employed in previous works.
Using articulatory data from five German speakers, we study how segmental sequences under different syllabic organizations respond to perturbations of phonetic parameters in the segments that compose them. Target words contained stop-lateral sequences /bl, gl, kl, pl/ in word-initial and cross-word contexts and were embedded in carrier phrases with different prosodic boundaries, i.e., no phrase boundary versus an utterance phrase boundary preceded the target word in the case of word-initial clusters, or separated the consonants in the case of cross-word sequences. For word-initial cluster (CCV) onsets, we find that increasing C1 stop duration or the lag between two consonants leads to earlier vowel initiation and reduced local timing stability across CV, CCV. Furthermore, as the inter-consonantal lag increases, C2 duration decreases. In contrast, for cross-word C#CV sequences, increasing inter-consonantal lag does not lead to earlier vowel initiation and robust local timing stability is maintained across CV, C#CV. In other words, in CCV sequences within words, local perturbations to segments have effects that ripple through the rest of the sequence. Instead, in cross-word C#CV sequences, local perturbations stay local. Overall, the findings indicate that the effects of phonetic perturbations on coordination patterns depend on the syllabic organization superimposed on these clusters.
This paper addresses the relation between syllable structure and inter-segmental temporal coordination. The data examined are Electromagnetic Articulometry recordings from six speakers of Central Peninsular Spanish (henceforth, Spanish), producing words beginning with the clusters /pl, bl, kl, gl, p(sic), k(sic), t(sic)/ as well as corresponding unclustered sonorant-initial words in three vowel contexts /a, e, o/. In our results, we find evidence for a global organization of the segments involved in these combinations. This is reflected in a number of ways: shortening of the prevocalic sonorant in the cluster-initial case compared to the unclustered case, reorganization of the relative timing of the internal CV subsequence (in a CCV) in the obstruent-lateral context, early vowel initiation, and a strong compensatory relation between the duration of the obstruent-to-lateral transition and the duration of the lateral. In other words, we find that the global organization presiding over the segments partaking in these tautosyllabic CCVs is pleiotropic, that is, simultaneously expressed over a set of different phonetic parameters rather than via a privileged metric such as c-center stability or any other such given single measure (employed in prior works).
In a cue-distractor task, speakers' response times (RTs) were found to speed up when they perceived a distractor syllable whose vowel was identical to the vowel in the syllable they were preparing to utter. At a more fine-grained level, subphonemic congruency between response and distractor-defined by higher number of shared phonological features or higher acoustic proximity-was also found to be predictive of RT modulations. Furthermore, the findings indicate that perception of vowel stimuli embedded in syllables gives rise to robust and more consistent perceptuomotor compatibility effects (compared to isolated vowels) across different response-distractor vowel pairs.
Fitts' law, perhaps the most celebrated law of human motor control, expresses a relation between the kinematic property of speed and the non-kinematic, task-specific property of accuracy. We aimed to assess whether speech movements obey this law using a metronome-driven speech elicitation paradigm with a systematic speech rate control. Specifically, using the paradigm of repetitive speech, we recorded via electromagnetic articulometry speech movement data in sequences of the form /CV.../ from 6 adult speakers. These sequences were spoken at 8 distinct rates ranging from extremely slow to extremely fast. Our results demonstrate, first, that the present paradigm of extensive metronome-driven manipulations satisfies the crucial prerequisites for evaluating Fitts' law in a subset of our elicited rates. Second, we uncover for the first time in speech evidence for Fitts' law at the faster rates and specifically beyond a participant-specific critical rate. We find no evidence for Fitts' law at the slowest metronome rates. Finally, we discuss implications of these results for models of speech.
Perceptuomotor compatibility between phonemically identical spoken and perceived syllables has been found to speed up response times (RTs) in speech production tasks. However, research on compatibility effects between perceived and produced stimuli at the subphonemic level is limited. Using a cue-distractor task, we investigated the effects of phonemic and subphonemic congruency in pairs of vowels. On each trial, a visual cue prompted individuals to produce a response vowel, and after the visual cue appeared a distractor vowel was auditorily presented while speakers were planning to produce the response vowel. The results revealed effects on RTs due to phonemic congruency (same vs. different vowels) between the response and distractor vowels, which resemble effects previously seen for consonants. Beyond phonemic congruency, we assessed how RTs are modulated as a function of the degree of subphonemic similarity between the response and distractor vowels. Higher similarity between the response and distractor in terms of phonological distance-defined by number of mismatching phonological features-resulted in faster RTs. However, the exact patterns of RTs varied across response-distractor vowel pairs. We discuss how different assumptions about phonological feature representations may account for the different patterns observed in RTs across response-distractor pairs. Our findings on the effects of perceived stimuli on produced speech at a more detailed level of representation than phonemic identity necessitate a more direct and specific formulation of the perception-production link. Additionally, these results extend previously reported perceptuomotor interactions mainly involving consonants to vowels.
This study focuses on the ability of the adult sound system to reorganise as a result of experience. Participants were exposed to existing and novel syllables in either a listening task or a production task over the course of two days. On the third day, they named disyllabic pseudowords while their electroencephalogram was recorded. The first syllable of these pseudowords had either been trained in the auditory modality, trained in production or had not been trained. The EEG response differed between existing and novel syllables for untrained but not for trained syllables, indicating that training novel sound sequences modifies the processes involved in the production of these sequences to make them more similar to those underlying the production of existing sound sequences. Effects of training on the EEG response were observed both after production training and mere auditory exposure.
The speed-curvature power law is a celebrated law of motor control expressing a relation between the kinematic property of speed and the geometric property of curvature. We aimed to assess whether speech movements obey this law just as movements from other domains do. We describe a metronome-driven speech elicitation paradigm designed to cover a wide range of speeds. We recorded via electromagnetic articulometry speech movements in sequences of the form /CV…/ from nine speakers (five German, four English) speaking at eight distinct rates. First, we demonstrate that the paradigm of metronome-driven manipulations results in speech movement data consistent with earlier reports on the kinematics of speech production. Second, analysis of our data in their full three-dimensions and using advanced numerical differentiation methods offers stronger evidence for the law than that reported in previous studies devoted to its assessment. Finally, we demonstrate the presence of a clear rate dependency of the power law’s parameters. The robustness of the speed-curvature relation in our datasets lends further support to the hypothesis that the power law is a general feature of human movement. We place our results in the context of other work in movement control and consider implications for models of speech production.
We offer a dynamical model of phonological planning that provides a formal instantiation of how the speech production and perception systems interact during online processing. The model is developed on the basis of evidence from an experimental task that requires concurrent use of both systems, the so-called response-distractor task in which speakers hear distractor syllables while they are preparing to produce required responses. The model formalizes how ongoing response planning is affected by perception and accounts for a range of results reported across previous studies. It does so by explicitly addressing the setting of parameter values in representations. The key unit of the model is that of the dynamic field, a distribution of activation over the range of values associated with each representational parameter. The setting of parameter values takes place by the attainment of a stable distribution of activation over the entire field, stable in the sense that it persists even after the response cue in the above experiments has been removed. This and other properties of representations that have been taken as axiomatic in previous work are derived by the dynamics of the proposed model. (C) 2016 Elsevier Inc. All rights reserved.