The releases of unvoiced aspirated stops in English are typically modeled as having three consecu... more The releases of unvoiced aspirated stops in English are typically modeled as having three consecutive phases, which overlap somewhat in time: (1) transient, (2) frication, and (3) aspiration. Close examination of stop releases reveals that the aspiration phase is more complicated than has been assumed. In this paper we explore the possibility that frication generated during the third phase may dominate the aspiration noise. This frication may be an extension of that generated at the original supraglottal constriction, or may be additional frication generated at a tongue-body or pharyngeal constriction formed in anticipation of the following vowel. Results suggest some subjects follow the classical model, but other subjects produce a mix of frication and aspiration during the third phase. Nevertheless, listeners do not have trouble with identification. We suggest that speakers can choose between using an extended burst or formant transitions to provide enhancing cues to place of arti...
COntains research objectives.U. S. Air Force (Electronic Systems Division) under Contract AF 19(6... more COntains research objectives.U. S. Air Force (Electronic Systems Division) under Contract AF 19(628)-3325National Science Foundation (Grant G-16526)National Institutes of Health (Grant MH-04737-03)National Institutes of Health (Grant NB-04332-01)National Aeronautics and Space Administration (Grant NsG-496
Over the past decades a number of research findings have illustrated the extraordinary robustness... more Over the past decades a number of research findings have illustrated the extraordinary robustness and flexibility of human speech perception, which combines sensitivity to surprisingly detailed aspects of systematic context-governed variability in word forms with an ability to extract information about the speaker's intended words from minimal information in a sometimes highly reduced signal. Stevens' [19] proposed model of human speech perception, based on the extraction of individual cues to distinctive features, provides an account of this robust perceptual processing in adults, and is also consistent with two recent findings about speech production during development in children learning American English: the occurrence of non-adult-like cues to the voicing contrast in coda stops, and the occurrence of adult-like cues in stop-like productions of voiced dental fricatives.
The Journal of the Acoustical Society of America, 2017
Changes in phonation patterns have long been studied as correlates of various linguistic elements... more Changes in phonation patterns have long been studied as correlates of various linguistic elements, such as the occurrence of irregular pitch periods (IPPs) at significant locations in prosodic structure (in phrase-initial, phrase-final, and pitch accented contexts) and word-final voiceless stops, especially /t/. But less is known about the development of this phonation pattern in children [cf. Song et al., JASA, 131, 3036-50, 2012], particularly in toddlers between the ages of 2;6 and 3;6. The study of its course of acquisition may shed light on the mechanisms involved, since child vocal folds are very different physiologically from those of adults, and change strikingly during development. Monosyllabic target words from the Imbrie Corpus of speech from 10 toddlers 2 1/2 to 3 1/2 years old, ending in /t, d/ were examined for evidence of IPPs. Preliminary results based on three adult/child pairs suggest that both adults and children produce IPPs preceding coda /t/ about 50% of the time. But children produc...
The Journal of the Acoustical Society of America, 2015
Ken’s background in physics and engineering and keen interest in phonetics gave him a rare abilit... more Ken’s background in physics and engineering and keen interest in phonetics gave him a rare ability to suggest a quantitative basis for distinctive features. His awareness that the acoustic correlate of a smoothly varying articulatory parameter might have a sudden change in value led to his development of Quantal Theory. In addition to providing a basis for distinctive contrasts, it provides a means for a continuous-time signal to reflect the discrete nature of the underlying representation of speech sounds. Later work led to two types of quantal relations: those based on aeromechanical properties of the vocal tract, which lead to manner features, and those based on coupling between cavities, which lead to articulator-bound features. Ken also suggested that each feature has a defining articulatory state, and thus, a defining acoustic correlate. Neighboring segments or higher-level phenomena may threaten the salience of defining acoustic correlates. Enhancement theory was developed to account for the fact that the defining articulatory or acoustic correlates are threatened in some environments. At such times, enhancing gestures that bolster the salience of the defining acoustic correlates are brought into play. Much of the work produced by Ken’s students was aimed at finding support for these theories.
The Journal of the Acoustical Society of America, 2010
ABSTRACT Fourier synthesis is the act of building a complex waveform from simple sine waves. Four... more ABSTRACT Fourier synthesis is the act of building a complex waveform from simple sine waves. Fourier analysis, on the other hand, decomposes a complex waveform into simple sine waves. Both Fourier synthesis and analysis are powerful tools in many scientific and engineering fields, allowing one to understand waveforms of all types in terms of their frequency content. In this experiment, Fourier synthesis will be brought to life as an acoustic waveform is built by combining several harmonic waves. A keyboard will generate the waves, which will then be observed using a computer.
Journal of Speech, Language, and Hearing Research, 2007
Purpose To describe cochlear implant users' phoneme labeling, discrimination, and prototypes ... more Purpose To describe cochlear implant users' phoneme labeling, discrimination, and prototypes for a vowel and a sibilant contrast, and to assess the effects of 1 year’s experience with prosthetic hearing. Method Based on naturally produced clear examples of “boot,” “beet,” “said,” and “shed” by 1 male and 1 female speaker, continua with 13 stimuli were synthesized for each contrast. Seven hearing controls labeled those stimuli and assigned them goodness ratings, as did 7 implant users at 1-month postimplant. One year later, these measures were repeated, and within category discrimination, d ′, was assessed. Results Compared with controls, implant users' vowel and sibilant labeling slopes were substantially shallower but improved over 1 year of prosthesis use. Their sensitivity to phonetic differences within phoneme categories was about half that of controls. The slopes of their goodness rating functions were shallower and did not improve. Their prototypes for the sibilant con...
Much of the information content in speech is conveyed by phonemic mechanisms, which consist of ne... more Much of the information content in speech is conveyed by phonemic mechanisms, which consist of neuro-muscular synergisms that achieve segmental articulatory and acoustic goals. Some of the goals are determined by quantal (nonlinear) relations between articulation and sound. The goals may also be influenced by other principles, such as a compromise between sufficient perceptual contrast and economy of articulatory effort. This leads to the prediction that the goal definitions correspond to regions (as opposed to ...
In previous work, we found evidence for trading relations between tongue-body raising and upper l... more In previous work, we found evidence for trading relations between tongue-body raising and upper lip protrusion (measured with an EMMA system) for the vowel/u/, reflecting a" motor equivalence" strategy that should help to constrain acoustic variation. Theoretically, analogous relations in the transformation between the area function and the acoustic transfer function are possible for the consonants/r/and/If/, which are also produced with two independently-controllable constrictions, formed by the tongue and by the lips. Such ...
The Journal of the Acoustical Society of America, 2014
A question of general interest is why languages have the sound categories that they do. K. N. Ste... more A question of general interest is why languages have the sound categories that they do. K. N. Stevens proposed the Quantal Theory of phonological contrasts, suggesting that regions of discontinuity in the articulatory-acoustic mapping serve as category boundaries. H. M. Hanson and K. N. Stevens [Proc. ICPhS, 182–185, 1995] modeled the interaction of subglottal resonances with the vocal-tract filter, showing that when a changing supraglottal formant strays into the territory of a stationary tracheal formant, a discontinuity in supraglottal formant frequency and attenuation of the formant peak occurs. They suggested that vowel space and quality could thus be affected. K. N. Stevens [Acoustic Phonetics, MIT Press, 1998] went further, musing that because the first and second subglottal resonances lead to instabilities in supraglottal formant frequency and amplitude, vowel systems would benefit by avoiding vowels with formants at these frequencies. Avoiding the first subglottal resonance would naturally lead t...
Child productions of two-syllable strong-weak words like baby and cookie are observed to exhibit ... more Child productions of two-syllable strong-weak words like baby and cookie are observed to exhibit a wide range of implementations of the medial stop consonant compared to adult productions. Detailed acoustic analysis of these consonants reported here lays the groundwork for prosodic analysis of the role of foot structure in the development of production of bisyllabic words. Acoustic details of the child productions differ significantly from those of the adults. The direction of these differences (e.g., longer durations, less pre-voicing) mean the child productions are more similar to an onset stop consonant of a two-syllable strong-weak word. However, children sometimes also reduce stop consonants in this environment to a greater extent than would an adult.
The current work is part of a project to characterize the subglottal pressure (Ps) contour associ... more The current work is part of a project to characterize the subglottal pressure (Ps) contour associated with a spoken utterance in terms of the distribution of pitch accents and of phrase and boundary tones. It is found that the nuclear pitch accent does not define the start of the termination phase; the utterance offset is a better marker. Declination rate of the working phase and its relation to the phrase and boundary tones at utterance offset are found to vary among speakers. The results have implications for models of speech production, and for applications such as computer speech synthesis and recognition.
Proceedings of the International Congress of Phonetic Sciences, 2007
The current work is part of a project to character-ize the subglottal pressure (Ps) contour assoc... more The current work is part of a project to character-ize the subglottal pressure (Ps) contour associated with a spoken utterance in terms of the distribution of pitch accents and of phrase and boundary tones. It is found that the nuclear pitch accent does not define the start of the termination phase; the utterance off-set is a better marker. Declination rate of the work-ing phase and its relation to the phrase and bound-ary tones at utterance offset are found to vary among speakers. The results have implications for models of speech production, and for applications such as computer speech synthesis and recognition.
Glottal characteristics of male speakers: Acoustic correlates and comparison with female data. [T... more Glottal characteristics of male speakers: Acoustic correlates and comparison with female data. [The Journal of the Acoustical Society of America 106, 1064 (1999)]. Helen M. Hanson, Erika S. Chuang. Abstract. Acoustic measurements ...
The releases of unvoiced aspirated stops in English are typically modeled as having three consecu... more The releases of unvoiced aspirated stops in English are typically modeled as having three consecutive phases, which overlap somewhat in time: (1) transient, (2) frication, and (3) aspiration. Close examination of stop releases reveals that the aspiration phase is more complicated than has been assumed. In this paper we explore the possibility that frication generated during the third phase may dominate the aspiration noise. This frication may be an extension of that generated at the original supraglottal constriction, or may be additional frication generated at a tongue-body or pharyngeal constriction formed in anticipation of the following vowel. Results suggest some subjects follow the classical model, but other subjects produce a mix of frication and aspiration during the third phase. Nevertheless, listeners do not have trouble with identification. We suggest that speakers can choose between using an extended burst or formant transitions to provide enhancing cues to place of arti...
COntains research objectives.U. S. Air Force (Electronic Systems Division) under Contract AF 19(6... more COntains research objectives.U. S. Air Force (Electronic Systems Division) under Contract AF 19(628)-3325National Science Foundation (Grant G-16526)National Institutes of Health (Grant MH-04737-03)National Institutes of Health (Grant NB-04332-01)National Aeronautics and Space Administration (Grant NsG-496
Over the past decades a number of research findings have illustrated the extraordinary robustness... more Over the past decades a number of research findings have illustrated the extraordinary robustness and flexibility of human speech perception, which combines sensitivity to surprisingly detailed aspects of systematic context-governed variability in word forms with an ability to extract information about the speaker's intended words from minimal information in a sometimes highly reduced signal. Stevens' [19] proposed model of human speech perception, based on the extraction of individual cues to distinctive features, provides an account of this robust perceptual processing in adults, and is also consistent with two recent findings about speech production during development in children learning American English: the occurrence of non-adult-like cues to the voicing contrast in coda stops, and the occurrence of adult-like cues in stop-like productions of voiced dental fricatives.
The Journal of the Acoustical Society of America, 2017
Changes in phonation patterns have long been studied as correlates of various linguistic elements... more Changes in phonation patterns have long been studied as correlates of various linguistic elements, such as the occurrence of irregular pitch periods (IPPs) at significant locations in prosodic structure (in phrase-initial, phrase-final, and pitch accented contexts) and word-final voiceless stops, especially /t/. But less is known about the development of this phonation pattern in children [cf. Song et al., JASA, 131, 3036-50, 2012], particularly in toddlers between the ages of 2;6 and 3;6. The study of its course of acquisition may shed light on the mechanisms involved, since child vocal folds are very different physiologically from those of adults, and change strikingly during development. Monosyllabic target words from the Imbrie Corpus of speech from 10 toddlers 2 1/2 to 3 1/2 years old, ending in /t, d/ were examined for evidence of IPPs. Preliminary results based on three adult/child pairs suggest that both adults and children produce IPPs preceding coda /t/ about 50% of the time. But children produc...
The Journal of the Acoustical Society of America, 2015
Ken’s background in physics and engineering and keen interest in phonetics gave him a rare abilit... more Ken’s background in physics and engineering and keen interest in phonetics gave him a rare ability to suggest a quantitative basis for distinctive features. His awareness that the acoustic correlate of a smoothly varying articulatory parameter might have a sudden change in value led to his development of Quantal Theory. In addition to providing a basis for distinctive contrasts, it provides a means for a continuous-time signal to reflect the discrete nature of the underlying representation of speech sounds. Later work led to two types of quantal relations: those based on aeromechanical properties of the vocal tract, which lead to manner features, and those based on coupling between cavities, which lead to articulator-bound features. Ken also suggested that each feature has a defining articulatory state, and thus, a defining acoustic correlate. Neighboring segments or higher-level phenomena may threaten the salience of defining acoustic correlates. Enhancement theory was developed to account for the fact that the defining articulatory or acoustic correlates are threatened in some environments. At such times, enhancing gestures that bolster the salience of the defining acoustic correlates are brought into play. Much of the work produced by Ken’s students was aimed at finding support for these theories.
The Journal of the Acoustical Society of America, 2010
ABSTRACT Fourier synthesis is the act of building a complex waveform from simple sine waves. Four... more ABSTRACT Fourier synthesis is the act of building a complex waveform from simple sine waves. Fourier analysis, on the other hand, decomposes a complex waveform into simple sine waves. Both Fourier synthesis and analysis are powerful tools in many scientific and engineering fields, allowing one to understand waveforms of all types in terms of their frequency content. In this experiment, Fourier synthesis will be brought to life as an acoustic waveform is built by combining several harmonic waves. A keyboard will generate the waves, which will then be observed using a computer.
Journal of Speech, Language, and Hearing Research, 2007
Purpose To describe cochlear implant users' phoneme labeling, discrimination, and prototypes ... more Purpose To describe cochlear implant users' phoneme labeling, discrimination, and prototypes for a vowel and a sibilant contrast, and to assess the effects of 1 year’s experience with prosthetic hearing. Method Based on naturally produced clear examples of “boot,” “beet,” “said,” and “shed” by 1 male and 1 female speaker, continua with 13 stimuli were synthesized for each contrast. Seven hearing controls labeled those stimuli and assigned them goodness ratings, as did 7 implant users at 1-month postimplant. One year later, these measures were repeated, and within category discrimination, d ′, was assessed. Results Compared with controls, implant users' vowel and sibilant labeling slopes were substantially shallower but improved over 1 year of prosthesis use. Their sensitivity to phonetic differences within phoneme categories was about half that of controls. The slopes of their goodness rating functions were shallower and did not improve. Their prototypes for the sibilant con...
Much of the information content in speech is conveyed by phonemic mechanisms, which consist of ne... more Much of the information content in speech is conveyed by phonemic mechanisms, which consist of neuro-muscular synergisms that achieve segmental articulatory and acoustic goals. Some of the goals are determined by quantal (nonlinear) relations between articulation and sound. The goals may also be influenced by other principles, such as a compromise between sufficient perceptual contrast and economy of articulatory effort. This leads to the prediction that the goal definitions correspond to regions (as opposed to ...
In previous work, we found evidence for trading relations between tongue-body raising and upper l... more In previous work, we found evidence for trading relations between tongue-body raising and upper lip protrusion (measured with an EMMA system) for the vowel/u/, reflecting a" motor equivalence" strategy that should help to constrain acoustic variation. Theoretically, analogous relations in the transformation between the area function and the acoustic transfer function are possible for the consonants/r/and/If/, which are also produced with two independently-controllable constrictions, formed by the tongue and by the lips. Such ...
The Journal of the Acoustical Society of America, 2014
A question of general interest is why languages have the sound categories that they do. K. N. Ste... more A question of general interest is why languages have the sound categories that they do. K. N. Stevens proposed the Quantal Theory of phonological contrasts, suggesting that regions of discontinuity in the articulatory-acoustic mapping serve as category boundaries. H. M. Hanson and K. N. Stevens [Proc. ICPhS, 182–185, 1995] modeled the interaction of subglottal resonances with the vocal-tract filter, showing that when a changing supraglottal formant strays into the territory of a stationary tracheal formant, a discontinuity in supraglottal formant frequency and attenuation of the formant peak occurs. They suggested that vowel space and quality could thus be affected. K. N. Stevens [Acoustic Phonetics, MIT Press, 1998] went further, musing that because the first and second subglottal resonances lead to instabilities in supraglottal formant frequency and amplitude, vowel systems would benefit by avoiding vowels with formants at these frequencies. Avoiding the first subglottal resonance would naturally lead t...
Child productions of two-syllable strong-weak words like baby and cookie are observed to exhibit ... more Child productions of two-syllable strong-weak words like baby and cookie are observed to exhibit a wide range of implementations of the medial stop consonant compared to adult productions. Detailed acoustic analysis of these consonants reported here lays the groundwork for prosodic analysis of the role of foot structure in the development of production of bisyllabic words. Acoustic details of the child productions differ significantly from those of the adults. The direction of these differences (e.g., longer durations, less pre-voicing) mean the child productions are more similar to an onset stop consonant of a two-syllable strong-weak word. However, children sometimes also reduce stop consonants in this environment to a greater extent than would an adult.
The current work is part of a project to characterize the subglottal pressure (Ps) contour associ... more The current work is part of a project to characterize the subglottal pressure (Ps) contour associated with a spoken utterance in terms of the distribution of pitch accents and of phrase and boundary tones. It is found that the nuclear pitch accent does not define the start of the termination phase; the utterance offset is a better marker. Declination rate of the working phase and its relation to the phrase and boundary tones at utterance offset are found to vary among speakers. The results have implications for models of speech production, and for applications such as computer speech synthesis and recognition.
Proceedings of the International Congress of Phonetic Sciences, 2007
The current work is part of a project to character-ize the subglottal pressure (Ps) contour assoc... more The current work is part of a project to character-ize the subglottal pressure (Ps) contour associated with a spoken utterance in terms of the distribution of pitch accents and of phrase and boundary tones. It is found that the nuclear pitch accent does not define the start of the termination phase; the utterance off-set is a better marker. Declination rate of the work-ing phase and its relation to the phrase and bound-ary tones at utterance offset are found to vary among speakers. The results have implications for models of speech production, and for applications such as computer speech synthesis and recognition.
Glottal characteristics of male speakers: Acoustic correlates and comparison with female data. [T... more Glottal characteristics of male speakers: Acoustic correlates and comparison with female data. [The Journal of the Acoustical Society of America 106, 1064 (1999)]. Helen M. Hanson, Erika S. Chuang. Abstract. Acoustic measurements ...
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