Articulatory-acoustic Relations Research Articles

Hadza liquid production and acoustics

Liquid systems in the world’s languages are relatively poorly understood. This study employs 3D/4D ultrasound methods to investigate articulatory characteristics of Hadza liquids produced by a single male speaker in a laboratory, analyzing simultaneously collected acoustic signals to determine relations between articulation and acoustics. Articulatory-acoustic relations are then compared to acoustic data obtained from other speakers collected in the field. Hadza is a language isolate spoken by approximately 1200 people (Brian Wood, pc.) in north-central Tanzania. Hadza is reported to have a single liquid phoneme which varies allophonically between a lateral approximant [l] occurring word-initially, and a tap [ɾ], occurring intervocalically (Tucker et al., 1977; Sands et al., 1996; Sands, 2013). The results of the current study confirm the production of both lateral approximant [l] and tap [ɾ] allophones; however, the results also show substantial variation between speakers. Furthermore, some speakers exhibit a categorical distinction between the allophones in given phonological environments, while others indicate a very similar articulation in both, and demonstrate no such distinction.

Segmental effects on the transmission of variability between articulation and acoustics

Previous research on articulatory-acoustic relations has generated conflicting results regarding the extent to which variability in articulation can be recovered from the acoustic signal (e.g., Guenther et al., 1999; Whalen etal., 2018). This study extends previous research probing the relationship between articulatory and acoustic variability by examining the extent to which individual differences in articulatory variability are recoverable from acoustics, and vice versa, for a set of American English consonants. A series of linear mixed effects regression models were fit to articulatory and acoustic data from tokens of /s/, /ʃ/, /l/, and /ɹ/ produced by 40 speakers in the Wisconsin X-Ray Microbeam Corpus (Westbury, 1994) to evaluate the extent to which the variability exhibited in one of these physical dimensions was recoverable from the signal in the other domain. The output of these statistical models was then compared to measurements of individual speakers’ variability along specific articulatory and acoustic dimensions to evaluate whether individual differences in variability were conveyed between articulation and acoustics. The results of the analyses suggest that the variability exhibited in one physical domain is to some extent recoverable from the other, although this capacity varies across segments and articulatory/acoustic dimensions. [Work supported by NIH.]

Variability in individual constriction contributions to third formant values in American English /ɹ/

Although substantial variability is observed in the articulatory implementation of the constriction gestures involved in /ɹ/ production, studies of articulatory-acoustic relations in /ɹ/ have largely ignored the potential for subtle variation in the implementation of these gestures to affect salient acoustic dimensions. This study examines how variation in the articulation of American English /ɹ/ influences the relative sensitivity of the third formant to variation in palatal, pharyngeal, and labial constriction degree. Simultaneously recorded articulatory and acoustic data from six speakers in the USC-TIMIT corpus was analyzed to determine how variation in the implementation of each constriction across tokens of /ɹ/ relates to variation in third formant values. Results show that third formant values are differentially affected by constriction degree for the different constrictions used to produce /ɹ/. Additionally, interspeaker variation is observed in the relative effect of different constriction gestures on third formant values, most notably in a division between speakers exhibiting relatively equal effects of palatal and pharyngeal constriction degree on F3 and speakers exhibiting a stronger palatal effect. This division among speakers mirrors interspeaker differences in mean constriction length and location, suggesting that individual differences in /ɹ/ production lead to variation in articulatory-acoustic relations.

Articulatory-acoustic relations in the production of alveolar and palatal lateral sounds in Brazilian Portuguese

Lateral approximant speech sounds are notoriously difficult to measure and describe due to their complex articulation and acoustics. This has prevented researchers from reaching a unifying description of the articulatory and acoustic characteristics of laterals. This paper examines articulatory and acoustic properties of Brazilian Portuguese alveolar and palatal lateral approximants (/l/ and /ʎ/) produced by six native speakers. The methodology for obtaining vocal tract area functions was based on three-dimensional/four-dimensional (3D/4D) ultrasound recordings and 3D digitized palatal impressions with simultaneously recorded audio signals. Area functions were used to calculate transfer function spectra, and predicted formant and anti-resonance frequencies were compared with the acoustic recordings. Mean absolute error in formant frequency prediction was 4% with a Pearson correlation of r = 0.987. Findings suggest anti-resonances from the interdental channels are less important than a prominent anti-resonance from the supralingual cavity but can become important in asymmetrical articulations. The use of 3D/4D ultrasound to study articulatory-acoustic relations is promising, but significant limitations remain and future work is needed to make better use of 3D/4D ultrasound data, e.g., by combining it with magnetic resonance imaging.

An acoustic-articulatory study of the nasal finals in students with and without hearing loss

The central aim of this experiment was to compare the articulatory and acoustic characteristics of students with normal hearing (NH) and school aged children with hearing loss (HL), and to explore the articulatory-acoustic relations during the nasal finals. Fourteen HL and 10 control group were enrolled in this study, and the data of 4 HL students were removed because of their high pronunciation error rate. Data were collected using an electromagnetic articulography. The acoustic data and kinematics data of nasal finals were extracted by the phonetics and data processing software, and all data were analyzed by t test and correlation analysis. The paper shows that, the difference was statistically significant ( P<0.05 or P<0.01) in different vowels under the first two formant frequencies (F1, F2), the tongue position and the articulatory-acoustic relations between HL and NH group. The HL group's vertical movement data-F1 relations in /en/ and /eng/ are same as NH group. The conclusion of this study about participants with HL can provide support for speech healing training at increasing pronunciation accuracy in HL participants.

Quantifying labial, palatal, and pharyngeal contributions to third formant lowering in American English /ɹ/

Although the acoustic profile of /ɹ/ is largely stable across speakers and contexts in rhotic dialects of American English (e.g., Hagiwara, 1995), significant variability is observed in the articulatory implementation of the palatal, pharyngeal, and labial constriction gestures involved in its production (Delattre &amp; Freeman, 1968; Alwan et al., 1999; Tiede et al., 2004). In order to quantify each gesture’s relative contribution to F3 lowering, we expand upon previous work on articulatory-acoustic relations in American English /ɹ/ by examining the acoustic effect of articulatory variation separately for each supralaryngeal constriction gesture. Real-time MRI data from four speakers in the USC-TIMIT corpus (Narayanan et al., 2014) were analyzed to determine the location, length, and aperture for each constriction gesture in 668 tokens of /ɹ/. Acoustic data were taken from simultaneous audio recordings of each speaker’s real-time MRI capture, with F1-F4 values extracted at the time of maximal constriction for each gesture. Our results suggest that each gesture’s acoustic contribution to F3 depends on between- and within-speaker variation in the articulation of /ɹ/, as variation in the length and location of the palatal and pharyngeal gestures is associated with differences in their relative effect size on F3 lowering. [Work supported by NIH.]

The emergence of phonetic–phonological features in a biologically inspired model of speech processing

Because speech acquisition begins with sensorimotor activity (i.e. babbling and imitation of speech items in order to learn articulatory–acoustic relations) as well as with semantic cognitive processing (i.e. linking phonetic items with concepts), distinctiveness as well as phonetic–phonological features emerge early in speech acquisition. Based on a biologically inspired model of speech processing, using interconnected growing self-organizing maps (I-GSOMs), the phonetic–phonological interface is described here in terms of a numerical computer-implemented model. By simulating early phases of speech acquisition, it can be shown that vocalic features like low–high as well as consonantal features describing the manner of articulation (like plosive, fricative, nasal, lateral, etc.) already arise at sensorimotor levels. This is reflected in our model by an ordering of syllables with respect to phonetic–phonological features at the level of an auditory based neural map. Other features like consonantal place of articulation (labial, apical, dorsal) as well as voiced–voiceless emerge at higher levels within our model, i.e. at the level of neural associations between a phonetic and a semantic neural map. It can be hypothesized from these findings that the phonetic–phonological interface does not appear as a clean cut within the speech processing system but as a broader zone within that system located between sensorimotor and semantic processing.

The quantal larynx revisited

Quantal effects signify nonlinear relations in the properties of speech sounds, traditionally emphasizing articulatory-acoustic relations [Stevens, J. Phonet. 17, 3–45 (1989)]; these relations hold important clues to how continuous phonetic parameters map onto discrete phonological categories. Stevens described quantal states in laryngeal speech function, showing how the vocal fold abduction-adduction continuum can be partitioned into breathy, modal, and pressed phonatory quanta. This account, however, relies on a one-dimensional conceptualization of the larynx, which recent developments in laryngeal phonetic theory reveal to be inadequate [Edmondson and Esling, Phonology 23, 157–191 (2006)]: a more realistic model must include the epilarynx. We reopen the issue of quantal laryngeal speech behavior in the context of recent research demonstrating quantal biomechanical properties in labial articulation [Gick et al., Can. Acoust. 39, 178–179 (2011)]. Our “whole larynx” approach [Moisik and Esling, ICPhS, 1406–1409 (2011)] countenances epilaryngeal influence on laryngeal articulatory and phonatory possibilities through quantal biomechanical and aero-mechanical effects. We demonstrate, through computer simulation, three novel cases of laryngeal quantality: (1) vocal-ventricular interaction in glottal stop, glottalization, and laryngealization; (2) aryepiglotto-epiglottal stricture in pharyngeal consonants; (3) epilaryngeal predisposition for growl-like or harsh phonation.

Articulatory-acoustic relations in Cantonese vowel production

The study investigates the quantal nature of two sets of Cantonese point vowels, the long [i: u:] in CV open syllables and the medium-long [i u] in CVS closed syllables, where S = stop consonant, by determining the articulatory-acoustic relations in the production of the four Cantonese point vowels. It evaluates Stevens' quantal theory (1972, 1989) by analyzing variability in articulation and acoustics of the four Cantonese point vowels. It also tests the sensitivity of formant frequencies of these point vowels to variation in linguo-palatal constriction location and degree of constriction along the vocal tract length. The investigation obtains variations in location and degree of linguo-palatal constriction along the vocal tract length during the point vowels, using EMMA AG500, and it relates the articulatory measurements to the corresponding vowel formant frequencies. Preliminary data show that the acoustic consequences of a shift in forward or backward direction of the constriction away from the target position for the point vowels are non-linear. The results appear to support the quantal nature of vowel production (Stevens, 1972, 1989). Furthermore, similar to the findings reported in Beckman, et al. (1995) formant frequencies are relatively less sensitive to variation in constriction location than degree of constriction.

Development of subglottal quantal effects in young children.

Quantal articulatory acoustic relations between formants and subglottal resonances have been shown to define several vowel and consonant distinctive features, including the vowel features (back) and (low). In particular, the F2 frequency of front vowels is higher than the second subglottal resonance (Sg2) but is lower than Sg2 for back vowels. Likewise for low vowels, F1 is higher than Sg1. Measurements of F1 and F2 for productions of the vowels /a/ and /ae/ were made on a number of occasions for several children in the age range 2.5–3.7 years. Measurements of Sg1 and Sg2 for each child were obtained from the locations of discontinuities in the F1 and F2 trajectories in diphthongs and in vowel-consonant transitions. At the earlier ages for these children, there was variability in the utterances, and the F1 and F2 values deviated from the expected relation. At the later age of 3 years and above, considerable agreement with the expected values of F1 and F2 in relation to the subglottal resonances was obtained. The transition from the expected quantal relation appears to occur in the age range between 2 and 3 years. [Work supported in part by NIH Grant R01-DC00075.]

Gender-specific articulatory–acoustic relations in vowel sequences

Differences in male and female vocal tract dimensions are hypothesized to have a number of dynamic consequences—differences in target attainment, articulatory speed, and acoustic vowel space dimension. Evidence for some of these predictions is sought by investigating articulatory and acoustic patterns in interword vowel sequences in the University of Wisconsin X-ray Microbeam Speech Production Database ( UW-XRMBDB). Means of formant and lingual pellet tracks throughout such vocalic stretches exhibit similarities in acoustic and articulatory form for male and female groups, but show significant gender-specific differences in both articulatory and acoustic space traversed, with females making greater acoustic excursions for shorter articulatory distances.

Geometry, kinematics, and acoustics of Tamil liquid consonants.

Tamil is unusual among the world's languages in that some of its dialects have five contrasting liquids. This paper focuses on the characterization of these sounds in terms of articulatory geometry and kinematics, as well as their articulatory-acoustic relations. This study illustrates the use of multiple techniques--static palatography, magnetic resonance imaging (MRI), and magnetometry (EMMA)--for investigating both static and dynamic articulatory characteristics using a single native speaker of Tamil. Dialectal merger and neutralization phenomena exhibited by the liquids of Tamil are discussed. Comparisons of English /[symbol: see text]/ and /l/ with Tamil provide evidence for generality in underlying mechanisms of rhotic and lateral production. The articulatory data justify the postulation of a class of rhotics and a class of laterals in Tamil, but do not provide evidence in favor of a larger class of liquids. Such a superclass appears to have largely an acoustic basis.

Critique: articulatory-acoustic relations and their role in speech perception.

These remarks are in response to "Role of articulation in speech perception: Clues from production"ony Björn Lindblom. It is suggested that the form in which the lexicon is stored includes both segments and distinctive features, and this representation is neutral with respect to articulatory and the acoustic domains. The process by which features are determined from the sound requires that patterns of acoustic properties be identified. In developing models of speech perception, knowledge of articulatory-acoustic relations can be a guide in defining these properties, but it is not necessary for the models to assign primary status to articulation.

On the quantal nature of speech

When a parameter specifying the configuration or state of an articulatory structure is manipulated through a range of values, some acoustic parameter describing the resulting sound often changes in a non-monotonic fashion. In particular, there appear to be ranges of the articulatory parameter for which there is very little change in the acoustic parameter and other ranges where the acoustic parameter is more sensitive to changes in articulation. The articulatory-acoustic relations are quantal in the sense that the acoustic patterns shows a change from one state to another as the articulatory parameter is varied through a range of values. Similar kinds of relations are observed between parameters that give a measure of the auditory response to a speechlike sound and parameters that specify some acoustic dimension of the sound. In this paper a number of examples of these types of acoustic-articulatory or auditory-acoustic relations are given. It is suggested that this tendency for quantal relations among these acoustic, auditory, and articulatory parameters is a principal factor shaping the inventory of acoustic and articulatory attributes that are used to signal distinctions in language.

Distinctive regions and modes: a new theory of speech production

A new explanatory and formal theory in speech production is presented. This theory is founded on perturbation theory and supported by computer simulation. Sensitivity functions which relate variations in formant frequency to small variations in area functions are revised in a manner that allows for their application to large variations in area functions. Available speech data are shown to confirm this theory, and known phonetic, articulatory and acoustic phenomena can be explained and embedded in a simple, global and formal model. The theory provides new insights into some principles of articulatory-acoustic relations and the application of these principles to phonetic theory. In this paper, several implications are studied: the articulatory-acoustic relation is simplified, the quantal nature of speech is confirmed, phonetic universals and phonetic systems are considered from a new point of view, formant transitions are explained and normalized, and an easy to control 9-parameter model proposed. We also consider other speech phenomena as interpreted by this theory such as compensatory and symmetry effects. The theory can also be used to formulate and calculate basic speech dynamic patterns. Several applications and research perspectives are proposed.