Acoustic consequences of articulatory variability during productions of /t/ and /k/ and its implications for speech error research (original) (raw)
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Articulatory variability and speech errors: An overview
Toronto working papers in linguistics (TWPL) 40, 2018
This paper presents an overview of a series of studies exploring the link between articulatory variability and speech errors in repetitive speech. The results from these articulatory speech error studies challenged the existence of phonemic speech errors and the findings necessitated a different approach of how errors should be interpreted. The objective of the paper is to evaluate how several researchers analyzed and interpreted the error data and summarizes several important findings with respect to the behavior and appearance of errors. Several psycholinguistic models are discussed that have been used to explain patterns of errors, including the cascading activation model and Articulatory Phonology.
The phonetics of phonological speech errors: An acoustic analysis of slips of the tongue
Journal of Phonetics, 2002
Phonological speech errors are a traditional source of evidence for phonological units like features and segments in both phonological and psycholinguistic theory. Assumptions about the unitary nature of speech errors have been brought into question by research that found evidence for sub-featural errors in speech production , Phonological primitives: Electro-myographic speech error evidence, Journal of the Acoustical Society of America, 88(3), 1299-1312]. Based on an articulatory study of speech errors, Mowrey and MacKay conclude that speech errors occur on a continuum of muscular activation, and that segmental errors are just the extreme cases that are perceptually anomalous. However, they analyzed electromyographic data from single muscles and thus were unable to determine whether single muscle activations occurred independently, or as part of larger gestural units. This paper examines the unitary nature of speech production acoustically. We find evidence for both featural and sub-featural errors in speech production. Our results support a model of speech production that hierarchically organizes individual gestural units into gestural constellations equivalent to linguistic segments. In addition, we find evidence for interaction between the lexical and gestural level, supporting connectionist models of speech error production.
Articulatory speech errors and word structure
2015
This study explores how identical final CV syllables in C1VC3V C2VC3V word pairs affect speech error patterns. Recent kinematic studies have shown that speakers frequently added non-intended movements to intended articulatory movements during the first consonants of C1VC3 C2VC3 syllables or reduce the range of the intended movements [1, 2, 3]. This effect was especially strong in syllables that contained identical final consonants, such as in switching from “cop top” to “top cop” [2]. It was hypothesized for the current study that C1VC3V C2VC3V word pairs, in which the second and fourth syllable were identical, would show similar intrusion and reduction patterns. Articulatory movements of the tongue tip, dorsum and lower lip were recorded with the 3D ElectroMagnetic Articulograph (AG501). Stimuli consisted of pairs of open and pairs of closed syllables. The findings revealed that CVCV CVCV word pairs resulted in significant more intrusions than CVC CVC word pairs.
Articulatory tradeoffs reduce acoustic variability during American English /r/ production
Journal of The Acoustical Society of America, 1999
The American English phoneme /r/ has long been associated with large amounts of articulatory variability during production. This paper investigates the hypothesis that the articulatory variations used by a speaker to produce /r/ in different contexts exhibit systematic tradeoffs, or articulatory trading relations, that act to maintain a relatively stable acoustic signal despite the large variations in vocal tract shape. Acoustic and articulatory recordings were collected from seven speakers producing /r/ in five phonetic contexts. For every speaker, the different articulator configurations used to produce /r/ in the different phonetic contexts showed systematic tradeoffs, as evidenced by significant correlations between the positions of transducers mounted on the tongue. Analysis of acoustic and articulatory variabilities revealed that these tradeoffs act to reduce acoustic variability, thus allowing relatively large contextual variations in vocal tract shape for /r/ without seriously degrading the primary acoustic cue. Furthermore, some subjects appeared to use completely different articulatory gestures to produce /r/ in different phonetic contexts. When viewed in light of current models of speech movement control, these results appear to favor models that utilize an acoustic or auditory target for each phoneme over models that utilize a vocal tract shape target for each phoneme.
Articulatory errors and word structure
Proceedings of the 18th International Congress of Phonetic Sciences, 2015
This study explores how identical final CV syllables in C1VC3V C2VC3V word pairs affect speech error patterns. Recent kinematic studies have shown that speakers frequently added non-intended movements to intended articulatory movements during the first consonants of C1VC3 C2VC3 syllables or reduce the range of the intended movements [1, 2, 3]. This effect was especially strong in syllables that contained identical final consonants, such as in switching from “cop top” to “top cop” [2]. It was hypothesized for the current study that C1VC3V C2VC3V word pairs, in which the second and fourth syllable were identical, would show similar intrusion and reduction patterns. Articulatory movements of the tongue tip, dorsum and lower lip were recorded with the 3D Electro-Magnetic Articulograph (AG501). Stimuli consisted of pairs of open and pairs of closed syllables. The findings revealed that CVCV CVCV word pairs resulted in significant more intrusions than CVC CVC word pairs.
Articulation Changes in Different Voicing Patterns
2007
Human speech arises from orchestrated activities of phonatory and articulatory organs and reflects human-specific characteristics in anatomy and physiology. The tongue and larynx are less tightly coupled in humans, and they are also innervated separately from the cortex. These biological specificities provide aerodynamic and acoustic bases of speech production and contribute to generating a parallel time-pattern of gradually changing vocal signals with ripples in amplitude and spectrum due to rapid articulatory movements. A close look at local sound variations suggests that tongue-larynx linkage still exists as an old trait common to the primate family, as seen in the variation of vocal frequency due to articulation. Contrarily, articulatory control may also be influenced by laryngeal control, as seen in irregular articulation in certain vocal expressions. Vowel devoicing may be a complex case of such bilateral interactions, and a special attention was made on the topic in this report.
Perception of place of articulation for plosives and fricatives in noise
Speech Communication, 2011
This study aims at uncovering perceptually-relevant acoustic cues for the labial versus alveolar place of articulation distinction in syllable-initial plosives tic analyses using logistic regression show that formant frequency measurements, relative spectral amplitude measurements, and burst/noise durations are generally reliable cues for labial/alveolar classification. In a subsequent perceptual experiment, each pair of syllables with the labial/alveolar distinction (e.g., /ba,da/) was presented to listeners in various levels of signal-to-noise-ratio (SNR) in a 2-AFC task. A threshold SNR was obtained for each syllable pair using sigmoid fitting of the percent correct scores. Results show that the perception of the labial/alveolar distinction in noise depends on the manner of articulation, the vowel context, and interaction between voicing and manner of articulation. Correlation analyses of the acoustic measurements and threshold SNRs show that formant frequency measurements (such as F1 and F2 onset frequencies and F2 and F3 frequency changes) become increasingly important for the perception of labial/alveolar distinctions as the SNR degrades.
Dissertation, 2014
This dissertation seeks to answer the question whether articulatory constraints and auditory information affect intrusion and reduction errors. These intrusions and reductions of articulatory movement result from a general tendency to stabilize movement coordination. Stabilisation of speech movement coordination is an autonomous self-organizing process. This process, however, can be affected by factors related to articulatory properties and auditory information.
Cortex, 2002
We present the case of two aphasic patients: one with fluent speech, MM, and one with dysfluent speech, DB. Both patients make similar proportions of phonological errors in speech production and the errors have similar characteristics. A closer analysis, however, shows a number of differences. DB's phonological errors involve, for the most part, simplifications of syllabic structure; they affect consonants more than vowels; and, among vowels, they show effects of sonority/complexity. This error pattern may reflect articulatory difficulties. MM's errors, instead, show little effect of syllable structure, affect vowels at least as much as consonants and, and affect all different vowels to a similar extent. This pattern is consistent with a more central impairment involving the selection of the right phoneme among competing alternatives. We propose that, at this level, vowel selection may be more difficult than consonant selection because vowels belong to a smaller set of repeatedly activated units.