Michael I Proctor

Michael I Proctor
Macquarie University · Department of Linguistics

Ph.D. Linguistics

About

87
Publications
11,229
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,093
Citations
Introduction
Michael I Proctor currently works at the Department of Linguistics, Macquarie University. Michael does research in Phonetics and Phonology.
Additional affiliations
July 2013 - June 2015
Macquarie University
Position
  • Lecturer
July 2012 - June 2013
The MARCS Institute, Western Sydney University
Position
  • Researcher
September 2009 - July 2012
University of Southern California
Position
  • PostDoc Position
Education
August 2004 - July 2009
Yale University
Field of study
  • Linguistics

Publications

Publications (87)
Conference Paper
Full-text available
Using eye-tracking in a visual world paradigm, we sought converging evidence for the time course of Mandarin Chinese tone recognition as predicted by the availability of information in f0 and past results from a gating experiment. Our results showed that tones 1 and 2 are recognized earlier than tone 4, followed by tone 3. With the exception of ton...
Article
To develop a real-time imaging technique that allows for simultaneous visualization of vocal tract shaping in multiple scan planes, and provides dynamic visualization of complex articulatory features. Simultaneous imaging of multiple slices was implemented using a custom real-time imaging platform. Midsagittal, coronal, and axial scan planes of the...
Article
Full-text available
Due to its aerodynamic, articulatory, and acoustic complexities, the fricative /s/ is known to require high precision in its control, and to be highly resistant to coarticulation. This study documents in detail how jaw, tongue front, tongue back, lips, and the first spectral moment covary during the production of /s/, to establish how coarticulatio...
Article
Acoustic studies have shown that in Australian English (AusE), vowel length contrasts are realised through temporal, spectral and dynamic characteristics. However, relatively little is known about the articulatory differences between long and short vowels in this variety. This study investigates the articulatory properties of three long–short vowel...
Article
Full-text available
Research on the temporal dynamics of /l/ production has focused primarily on mid-sagittal tongue movements. This study reports how known variations in the timing of mid-sagittal gestures are related to para-sagittal dynamics in /l/ formation in Australian English (AusE), using three-dimensional electromagnetic articulography (3D EMA). The articulat...
Article
Full-text available
In Australian English rimes, coarticulation between coda /l/ and its preceding vowel has the potential to attenuate cues that contribute to phonological vowel contrast. Therefore, vowel-/l/ coarticulation may increase ambiguity between prelateral vowels. We used a vowel identification task to test the effect of vowel-/l/ coarticulation on vowel dis...
Article
Vowel contrasts may be reduced or neutralized before coda laterals in English [Bernard (1985). The Cultivated Australian: Festschrift in Honour of Arthur Delbridge, pp. 319–332; Labov, Ash, and Boberg (2008). The Atlas of North American English, Phonetics and Sound Change (Gruyter Mouton, Berlin); Palethorpe and Cox (2003). International Seminar on...
Article
A key method for studying articulatory planning at different levels of phonological organization is masked-onset priming. In previous work using that paradigm the dependent variable has been acoustic response time (RT). We used electromagnetic articulography to measure articulatory RTs and the articulatory properties of speech gestures in non-word...
Chapter
Our understanding of clicks has been limited in some important respects by the technologies available for phonetic research. New insights into click production are available through the use of real-time Magnetic Resonance Imaging, which offers dynamic information about the midsagittal configuration of the entire vocal tract, including the velum, to...
Preprint
Full-text available
Articulography and functional neuroimaging are two major tools for studying the neurobiology of speech production. Until now, however, it has generally not been possible to use both in the same experimental setup because of technical incompatibilities between the two methodologies. Here we describe results from a novel articulography system dubbed...
Article
Articulation of liquid consonants in onsets and codas by four speakers of General American English was examined using real-time MRI. Midsagittal tongue posture was compared for laterals and rhotics produced in each syllable margin, adjacent to 13 different vowels and diphthongs. Vowel articulation was examined in words without liquids, before each...
Conference Paper
Full-text available
Parkinson's disease (PD) is a neurological disorder that is characterized by a decay in global motor performance, manifest in tremor, abnormal gait, and dysarthria. PD dysarthria characteristics include monoloudness, pathological voice quality, and imprecise articulation. Standard treatment for relieving PD symptoms is the drug levodopa, but it is...
Conference Paper
Full-text available
Articulatory coordination in English phonemic vowel length contrasts has not been systematically explored. Australian English (AusE), which has a true phonemic vowel length contrast in the open vowels /ɐː-ɐ/ (as in tart-tut), provides a natural control case for exploring articulatory vowel length. Intergestural coordination was examined using Elect...
Article
Language-specific maximal size restrictions on syllables have been defined using frames such as moraic structure. In General American English, a trimoraic syllable template makes largely successful predictions about contexts where tense/lax vowel contrasts are neutralised, but neutralisation preceding a coda rhotic has not been adequately explained...
Article
Full-text available
Punjabi (Western, ISO-639-3 pnb) is an Indo-Aryan language (Indo-European, Indo-Iranian) spoken in Pakistan and India, and in immigrant communities in the UK, Canada, USA, and elsewhere. In terms of number of native speakers, it is ranked 10th among the world’s languages, with more than 100 million speakers (Lewis, Simons & Fennig 2016). Aspects of...
Article
Moroccan Arabic uses geminate/singleton contrasts in medial position but it is controversial whether it maintains them utterance-initially. To address this issue, we made simultaneous ultrasound and acoustic recordings of five native speakers producing target words containing /t/-/tt/ and /d/-/dd/ contrasts utterance-initially and -medially, 10 tim...
Article
Recent advances in real-time magnetic resonance imaging (RT-MRI) have made it possible to study the anatomy and dynamic motion of the vocal tract during speech production with great detail. The abundance of rich data on speech articulation provided by medical imaging techniques affords new opportunities for speech science, linguistics, clinical and...
Conference Paper
Full-text available
This study investigated the dynamics of lateral channel formation of /l/ in Australian-accented English (AusE) using 3D electromagnetic articulography (EMA). Coils were placed on the tongue both mid-sagitally and para-sagitally. We varied the vowel precedi /l/ between /I/ and /æ/ /a.g, filbert vs. talbot, and the syllable position of /l/, e.g., /'t...
Article
Full-text available
The phonological category “retroflex” is found in many Indo-Aryan languages; however, it has not been clearly established which acoustic characteristics reliably differentiate retroflexes from other coronals. This study investigates the acoustic phonetic properties of Punjabi retroflex /ʈ/ and dental /ʈ̪/ in word-medial and word-initial contexts ac...
Article
Full-text available
Purpose: Real-time magnetic resonance imaging (MRI) and accompanying analytical methods are shown to capture and quantify salient aspects of apraxic speech, substantiating and expanding upon evidence provided by clinical observation and acoustic and kinematic data. Analysis of apraxic speech errors within a dynamic systems framework is provided an...
Conference Paper
Articulation of vowels produced by a single speaker of Australian English in CVC contexts was examined using Electromagnetic Articulography. Dorsal articulatory activity for each vowel was compared by tracking the midsagittal trajectories of the tongue body. Articulatory targets were determined and a companion articulatory vowel space constructed....
Article
Full-text available
Purpose: Models of speech production often abstract away from shared physiology in pitch control and lingual articulation, positing independent control of tone and vowel units. We assess the validity of this assumption in Mandarin Chinese by evaluating the stability of lingual articulation for vowels across variation in tone. Method: Electromagn...
Article
Characteristic tongue postures of 21,478 vowels produced by four speakers of General American English were compared in lexically stressed and unstressed positions to examine patterns of articulation and reduction. Image frames capturing midsagittal vocal tract configurations were reconstructed at the acoustic midpoint of each vowel produced in a 3,...
Article
In General American English (GAE), tense/lax vowel contrasts occur before syllables ending in /l/ (e.g., peel, pill), but not those ending in /ɹ/ (e.g., peer; no [i]/[ɪ] contrast). No such restrictions occur after a syllable-initial liquid consonant (e.g., lip, leap, rip, reap). This study investigates the hypothesis that these phonotactic asymmetr...
Conference Paper
Full-text available
There is evidence that coronal contrasts involving retroflexes are less clearly distinguished after a high front vowel /i/ [2, 9]. However, no detailed acoustic studies have been conducted to investigate whether following front vowels affect the contrastiveness of dentals, retroflexes and palatals. We examined the acoustic characteristics of three...
Conference Paper
Full-text available
Languages which make use of three or four-way place contrasts in coronal obstruents are relatively rare (Ladefoged & Maddieson, 1996). Different acoustic cues have been shown to be associated with different coronal places of articulation: (a) retroflexes are characterized by shorter closure and burst durations (Tabain, 2012), (b) lower frequency bu...
Article
USC-TIMIT is an extensive database of multimodal speech production data, developed to complement existing resources available to the speech research community and with the intention of being continuously refined and augmented. The database currently includes real-time magnetic resonance imaging data from five male and five female speakers of Americ...
Conference Paper
Full-text available
We studied tone-vowel coproduction using Electromagnetic Articulography (EMA). Fleshpoints on the tongue and jaw were tracked while native Chinese speakers (n = 6) produced three vowels, /a/, /i/, /u/, combined with four Chinese tones. We found differences in tongue position across tones for /a/ and for /i/ but not for /u/. The low and rising tones...
Article
Purpose: Differences in vocal tract morphology have the potential to explain interspeaker variability in speech production. The potential acoustic impact of hard palate shape was examined in simulation, in addition to the interplay among morphology, articulation, and acoustics in real vowel production data. Method: High-front vowel production fr...
Article
The tongue varies across speakers in terms of the proportion of the overall speech production apparatus that it occupies. Differences in tongue size have the potential to result in speaker-specific articulatory strategies for shaping the vocal tract area function and, in turn, individual patterns of vowel acoustics. The present study examines the i...
Article
In General American English (GAE), only two full vowels [ɑ, ɔ] occur in syllables ending in [ɹ] plus a non-coronal consonant, e.g., , . An articulatory study of rhotic production by three speakers of GAE was conducted using real-time structural magnetic resonance imaging (rtMRI) [Narayanan et al. (2004)]. Subjects produced /ɹ/ in simple and complex...
Article
Speech production can be described in multiple coordinate frames: articulatory configurations, gestural tasks, and acoustic patterns. Examination of the achievement of retroflex stops and liquids in Tamil suggests that we must consider separately the gestural task of apical pre-palatal constriction and the articulatory maneuver to achieve the task....
Article
Full-text available
Purpose: Adult human vocal tracts display considerable morphological variation across individuals, but the nature and extent of this variation has not been extensively studied for many vocal tract structures. There exists a need to analyze morphological variation and, even more basically, to develop a methodology for morphological analysis of the...
Article
Full-text available
Real-time Magnetic Resonance Imaging (rtMRI) was used to examine mechanisms of sound production by an American male beatbox artist. rtMRI was found to be a useful modality with which to study this form of sound production, providing a global dynamic view of the midsagittal vocal tract at frame rates sufficient to observe the movement and coordinati...
Article
Full-text available
Production of nasal vowels in French, and nasal consonants in French and English, was examined using real-time magnetic resonance imaging (rtMRI). The coordination of velic and lingual gestures was found to be tightly controlled across different prosodic contexts in French nasals. Velum lowering in English nasal consonants did not show the same con...
Article
Real-Time Magnetic Resonance Imaging affords speech articulation data with good spatial and temporal resolution and complete midsagittal views of the moving vocal tract, but also brings many challenges in the domain of image processing and analysis. Region-of-interest analysis has previously been proposed for simple, efficient and robust extraction...
Article
A real-time MRI examination of retroflex stops and rhotics in Tamil reveals that in some contexts these consonants may in fact be achieved with little or no retroflexion of the tongue tip. Rather, maneuvering and shaping of the tongue in order to achieve post-alveolar contact varies across vowel contexts. Between back vowels /a/ and /u/, post-alveo...
Article
Full-text available
Noninvasive imaging is widely used in speech research as a means to investigate the shaping and dynamics of the vocal tract during speech production. 3D dynamic MRI would be a major advance, as it would provide 3D dynamic visualization of the entire vocal tract. We present a novel method for the creation of 3D dynamic movies of vocal tract shaping...
Conference Paper
Full-text available
We explore the use of real-time magnetic resonance imaging (rtMRI) as a tool to investigate apraxic speech, in particular, by examining articulatory behavior. Our pilot data reveal that covert (silent) gestural intrusion errors (employing an intrinsically simple 1:1 mode of coupling) are made more frequently by an apraxic subject than by fluent spe...
Conference Paper
Production of emphatic consonants by a speaker of Lebanese Arabic was examined using real-time magnetic resonance imaging (rtMRI). Emphatic consonants were found to be articulated with a lowered, more retracted tongue body than their nonempatic counterparts, with the narrowest emphatic constriction observed in the upper pharynx. Both progressive an...
Article
We propose a method for co-registrating speech articulatory/acoustic data from two modalities that provide complementary advantages. Electromagnetic Articulography (EMA) provides high temporal resolution (100 samples/second in WAVE system) and flesh-point tracking, while real-time Magnetic Resonance Imaging, rtMRI, (23 frames/second) offers a compl...
Chapter
Sonority is generally considered to play a primary role in governing intrasyllabic phonotactics. In this chapter, we examine the phonotactic and articulatory properties of tautosyllabic vowel-liquid sequences in American English, and consider the implications for theories of sonority. Constraints on the distribution of vowels preceding liquid codas...
Article
Research on geminate consonants has attempted to establish whether the control of their articulation differs from that of corresponding singletons in temporal parameters, spatial parameters, or both. One piece of evidence supporting spatial control in Italian geminates is EPG results revealing that the location of maximal constriction (CL) of coron...
Article
Although volumetric magnetic resonance imaging has proven to be a valuable tool in the study of consonant production (Narayanan etal., 1995; Kröger etal., 2000), its utility is limited by the difficulty and laboriousness of reliably extracting tissue boundaries from imaging data. Current methods typically involve manual segmentation of air-tissue b...
Article
Full-text available
Although native English speakers have strong intuitions about the felicity of different reading styles, it is unclear which properties of read speech contribute to these reactions. Although the prosodic structures of read speech and spontaneous speech have been shown to differ (Howell and Kadi-Hanifi, 1991; Blaauw, 1994), it is not clear whether si...
Article
It has been shown that subjects may recruit extra-linguistic articulators during the rhythmic production of speech (Tiede, 2010), that sympathetic head movement is associated with dysfluencies in running speech (Hadar, 1984), and that the magnitude of this activity positively correlates with both speaking rate and increased effort in accelerating s...
Conference Paper
Full-text available
We present MRI-TIMIT: a large-scale database of synchronized audio and real-time magnetic resonance imaging (rtMRI) data for speech research. The database currently consists of speech data acquired from two male and two female speakers of American English. Subjects' upper airways were imaged in the midsagittal plane while reading the same 460 sente...
Conference Paper
Full-text available
Conventional real-time magnetic resonance imaging (RT-MRI) of the upper airway typically acquires information about the vocal tract from a single midsagittal scan plane. This provides insights into the dynamics of all articulators, but does not allow for visualization of several important features in vocal tract shaping, such as grooving/doming of...
Conference Paper
Full-text available
In order to fully understand inter-speaker variability in the acoustical and articulatory domains, morphological variability must be considered, as well. Human vocal tracts display substantial morphological differences, all of which have the potential to impact a speaker's acoustic output. The palate and rear pharyngeal wall, in particular, vary wi...
Conference Paper
Full-text available
A method of rapid, automatic extraction of consonantal articulatory trajectories from real-time magnetic resonance image sequences is described. Constriction location targets are estimated by identifying regions of maximally-dynamic correlated pixel activity along the palate, the alveolar ridge, and at the lips. Tissue movement into and out of the...
Article
Full-text available
The production of intervocalic liquid consonants by five speakers of Spanish and four speakers of Russian was examined using ultrasound. Liquids in both languages were found to be united by a lower susceptibility to vocalic coarticulation than coronal obstruents produced in the same environments. Tongue body articulation in the Spanish lateral rese...
Article
Articulometry studies have demonstrated that speech errors often involve gestural intrusions that are coproduced with other gestures and can go unnoticed because they are not always perceived to be segmental errors. [Mowrey and MacKay (1990)]. Real time magnetic resonance imaging was used to examine tongue movement during the production of English...
Article
Apical trills last about 150 ms, with individual closure and opening parts between 10 and 30 ms. [Ladefoged et al., J. Int. Phonetic Assoc. 7, 46-54 (1977).] A digital ultrasound study revealed articulatory details correlated with spectral output. The Haskins Digital Ultrasound System allowed imaging at 127 Hz of apical trills in Russian and Spanis...
Article
Full-text available
A structural magnetic resonance imaging study has revealed that pharyngeal articulation varies considerably with voicing during the production of English fricatives. In a study of four speakers of American English, pharyngeal volume was generally found to be greater during the production of sustained voiced fricatives, compared to voiceless equival...
Conference Paper
Full-text available
Realtime MRI provides useful data about the human vocal tract, but also introduces many of the challenges of processing high-dimensional image data. Intuitively, data reduction would proceed by finding the air-tissue boundaries in the images, and tracing an outline of the vocal tract. This approach is anatomically well-founded. We explore an altern...
Conference Paper
Full-text available
A method of rapid semi-automatic segmentation of real-time magnetic resonance image data for parametric analysis of vocal tract shaping is described. Tissue boundaries are identified by seeking pixel intensity thresholds along tract-normal grid-lines. Airway contours are constrained with respect to a tract centerline defined as an optimal path over...