Theory Of Speech Production Research Articles

Detection of Voice Pathology using Fractal Dimension in a Multiresolution Analysis of Normal and Disordered Speech Signals.

Voice disorders are associated with irregular vibrations of vocal folds. Based on the source filter theory of speech production, these irregular vibrations can be detected in a non-invasive way by analyzing the speech signal. In this paper we present a multiband approach for the detection of voice disorders given that the voice source generally interacts with the vocal tract in a non-linear way. In normal phonation, and assuming sustained phonation of a vowel, the lower frequencies of speech are heavily source dependent due to the low frequency glottal formant, while the higher frequencies are less dependent on the source signal. During abnormal phonation, this is still a valid, but turbulent noise of source, because of the irregular vibration, affects also higher frequencies. Motivated by such a model, we suggest a multiband approach based on a three-level discrete wavelet transformation (DWT) and in each band the fractal dimension (FD) of the estimated power spectrum is estimated. The experiments suggest that frequency band 1-1562 Hz, lower frequencies after level 3, exhibits a significant difference in the spectrum of a normal and pathological subject. With this band, a detection rate of 91.28 % is obtained with one feature, and the obtained result is higher than all other frequency bands. Moreover, an accuracy of 92.45 % and an area under receiver operating characteristic curve (AUC) of 95.06 % is acquired when the FD of all levels is fused. Likewise, when the FD of all levels is combined with 22 Multi-Dimensional Voice Program (MDVP) parameters, an improvement of 2.26 % in accuracy and 1.45 % in AUC is observed.

Lexical frequency effects on articulation: a comparison of picture naming and reading aloud.

The present study investigated whether lexical frequency, a variable that is known to affect the time taken to utter a verbal response, may also influence articulation. Pairs of words that differed in terms of their relative frequency, but were matched on their onset, vowel, and number of phonemes (e.g., map vs. mat, where the former is more frequent than the latter) were used in a picture naming and a reading aloud task. Low-frequency items yielded slower response latencies than high-frequency items in both tasks, with the frequency effect being significantly larger in picture naming compared to reading aloud. Also, initial-phoneme durations were longer for low-frequency items than for high-frequency items. The frequency effect on initial-phoneme durations was slightly more prominent in picture naming than in reading aloud, yet its size was very small, thus preventing us from concluding that lexical frequency exerts an influence on articulation. Additionally, initial-phoneme and whole-word durations were significantly longer in reading aloud compared to picture naming. We discuss our findings in the context of current theories of reading aloud and speech production, and the approaches they adopt in relation to the nature of information flow (staged vs. cascaded) between cognitive and articulatory levels of processing.

Bridging computational approaches to speech production: The semantic-lexical-auditory-motor model (SLAM).

Speech production is studied from both psycholinguistic and motor-control perspectives, with little interaction between the approaches. We assessed the explanatory value of integrating psycholinguistic and motor-control concepts for theories of speech production. By augmenting a popular psycholinguistic model of lexical retrieval with a motor-control-inspired architecture, we created a new computational model to explain speech errors in the context of aphasia. Comparing the model fits to picture-naming data from 255 aphasic patients, we found that our new model improves fits for a theoretically predictable subtype of aphasia: conduction. We discovered that the improved fits for this group were a result of strong auditory-lexical feedback activation, combined with weaker auditory-motor feedforward activation, leading to increased competition from phonologically related neighbors during lexical selection. We discuss the implications of our findings with respect to other extant models of lexical retrieval.

Homophony and morphology: The acoustics of word-final S in English

Recent research has shown that homophonous lexemes show systematic phonetic differences (e.g. Gahl 2008, Drager 2011), with important consequences for models of speech production such as Levelt et al. (1999). These findings also pose the question of whether similar differences hold for allegedly homophonous affixes (instead of free lexemes). Earlier experimental research found some evidence that morphemic and non-morphemic sounds may differ acoustically (Walsh & Parker 1983, Losiewicz 1992). This paper investigates this question by analyzing the phonetic realization of non-morphemic /s/ and /z/, and of six different English /s/ and /z/ morphemes (plural, genitive, genitive-plural and 3rd person singular, as well as cliticized forms ofhasandis). The analysis is based on more than 600 tokens extracted from conversational speech (Buckeye Corpus, Pitt et al. 2007). Two important results emerge. First, there are significant differences in acoustic duration between some morphemic /s/’s and /z/’s and non-morphemic /s/ and /z/, respectively. Second, there are significant differences in duration between some of the morphemes. These findings challenge standard assumptions in morphological theory, lexical phonology and models of speech production.

Masked primes activate feature representations in reading aloud.

Theories of reading aloud are silent about the role of subphonemic/subsegmental representations in translating print to sound. However, there is empirical evidence suggesting that feature representations are activated in speech production and visual word recognition. In the present study, we sought to determine whether masked primes activate feature representations in reading aloud using a variation of the masked onset priming effect (MOPE). We found that target nonwords (e.g., BAF) were read aloud faster when preceded by masked nonword primes that shared their initial phoneme with the target (e.g., bez), or primes whose initial phoneme shared all features except voicing with the first phoneme of the target (e.g., piz), compared with unrelated primes (e.g., suz). We obtained the same result in 2 experiments that used different participants and prime durations (around 60 ms in Experiment 1 and 50 ms in Experiment 2). The significant masked feature priming effect that was observed in both experiments converges with the empirical evidence in the speech production and visual word recognition domains indicating a functional role for features in reading aloud. Our findings motivate the further development of current theories of reading aloud and have important implications for extant theories of speech production.

ESTUDO DA VARIAÇÃO LINGUÍSTICA DOS RÓTICOS NO FALAR CAMPINEIRO

Este artigo apresenta resultados de uma pesquisa que buscou investigar a variação de um segmento linguístico do falar campineiro: o /R/ em posição de coda silábica. Como hipótese principal deste estudo, assumiu-se que o rótico produzido pelos informantes campineiros estaria em um estado mais avançado, se comparado a outras cidades do interior paulista, no que se refere ao enfraquecimento desse segmento, tendendo à vocalização ou ao apagamento. Esse enfraquecimento seria o responsável pela impressão, de oitiva, dos informantes que julgam pronunciar uma variante de /R/ avaliada como “intermediária” e indicada como característica do falar campineiro. O corpus selecionado consta de dados coletados junto a doze informantes naturais do interior paulista. Esses dados foram gravados e submetidos à análise acústica e estatística. Para análise dos dados, o referencial teórico adotado foi o da Teoria Acústica de Produção da Fala, conforme Fant (1970), somado aos pressupostos da Sociolinguística. Os resultados alcançados nesta pesquisa mostram que há variação linguística do rótico e que a variante mais frequente é o /R/ caipira. Esse resultado contraria a alegada existência de um /R/ característico do falar campineiro.

Functional significance of the electrocorticographic auditory responses in the premotor cortex.

Other than well-known motor activities in the precentral gyrus, functional magnetic resonance imaging (fMRI) studies have found that the ventral part of the precentral gyrus is activated in response to linguistic auditory stimuli. It has been proposed that the premotor cortex in the precentral gyrus is responsible for the comprehension of speech, but the precise function of this area is still debated because patients with frontal lesions that include the precentral gyrus do not exhibit disturbances in speech comprehension. We report on a patient who underwent resection of the tumor in the precentral gyrus with electrocorticographic recordings while she performed the verb generation task during awake brain craniotomy. Consistent with previous fMRI studies, high-gamma band auditory activity was observed in the precentral gyrus. Due to the location of the tumor, the patient underwent resection of the auditory responsive precentral area which resulted in the post-operative expression of a characteristic articulatory disturbance known as apraxia of speech (AOS). The language function of the patient was otherwise preserved and she exhibited intact comprehension of both spoken and written language. The present findings demonstrated that a lesion restricted to the ventral precentral gyrus is sufficient for the expression of AOS and suggest that the auditory-responsive area plays an important role in the execution of fluent speech rather than the comprehension of speech. These findings also confirm that the function of the premotor area is predominantly motor in nature and its sensory responses is more consistent with the “sensory theory of speech production,” in which it was proposed that sensory representations are used to guide motor-articulatory processes.

Carroll's Autonomous Induction Theory: Combining Views from UG and Information Processing Theories

Without other mechanisms such as induction and parsers, UG-based approaches to linguistic cognition seem to fail to explain the logical problem of language acquisition. Hence, a property theory has to be adopted to combine UG views with other cognitive mechanisms like information processing and restructuring (Ellis, 2008). Pienemann (1998, 2003)'s Processibility Theory, and Levelt’s (1989) psycholinguistic theory of speech production, Jackendof's (1987, 1997, 2002) MOGUL, and Carroll’s (2001, 2002) Autonomous Induction Theory (AIT) are among the models which try to add new views to the UG-based approaches. Although suffering from a number of criticisms and having a high degree of abstractness, AIT with its major premises and conceptions related to the role of induction, attention, input, input processing, feedback, learning, and UG seems to be able to explain some of the UG enigma in second language acquisition.

Syllable and Segments Effects in Mandarin Chinese Spoken Word Production

Speaking involves stages of conceptual preparation, lemma selection, word-form encoding and articulation.Furthermore, process of word-form encoding can be divided into morphological encoding process, phonological encoding process and phonetic encoding. What is the function unit at the stage of word-form encoding remains a controversial issue in speech production theories. The present study investigated syllable and segments effects at the stages of phonological encoding, phonetic encoding, and articulation in Mandarin spoken word production.Using Picture-Word Interference(PWI) Paradigm, we compared the effects generated in immediately naming(experiment 1), delayed naming(experiment 2), and delayed naming combined with articulation suppression(experiment 3) tasks. Eighteen black and white line drawings were applied as stimuli, and their names were monosyllabic words. Each target picture was paired with four distractor words: A CVC-related(C:Consonant, V: Vowel) distractor word was chosen that shared a syllable which always differed in tone with the picture name(i.e., 羊 /yang2/ as target name- 央 /yang1/ as distractor word). A CV-related distractor word was chosen that shared the onset consonant and the core vowel with the picture name(i.e., 羊 /yang2/- 药 /yao4/). A VC-related distractor was chosen that shared the rhymes with the picture name(i.e., 羊 /yang2/- 让 /rang4/). An unrelated distractor was selected that stood in no obvious semantic, phonological or orthographic relation with the picture name.We found syllable and segments facilitation effects in immediate naming, whereas syllable and segments inhibition effects in a delayed naming and a combination task of delayed naming and articulation suppression.An immediate naming involves stages of phonological encoding, phonetic encoding, and articulation, a delayed naming involves articulation only, while a combination task of delayed naming and articulation suppression involves phonetic encoding and articulation processes.By comparing these effects among three tasks, we suggest that syllable and segments facilitation effects localized at the stage of phonological encoding, whereas syllable and segments inhibition effects localized at the stage of phonetic encoding and(or) articulation. These findings indicated that syllable plays a more important role in phonological encoding whereas segments play their roles in phonetic encoding and articulation for motor programming. Our findings provide support for Proximate Unit Principle and the assumption of independence of premotor-(phonological encoding) and motor stages(phonetic encoding and articulation).

Socially-mediated syntactic alignment

AbstractWhen we interact with one another, we tend to align our behaviors, including the way we talk. Psycholinguistic work has conceptualized alignment as the result of automatic cognitive mechanisms that operate to facilitate processing and communication. Sociolinguistic work has focused on the role of social identity and interactional strategy in explaining linguistic alignment. We draw on these two largely distinct traditions to investigate socially mediated syntactic alignment with the goal of understanding how social perception and cognition influence the mechanisms involved in alignment. A novel web-based paradigm was employed to collect speech data from a large socially heterogeneous sample. Participants listened to one of three speakers, each with a different accent, deliver an ideologically charged diatribe. Participants then completed a picture description task to assess the degree of syntactic alignment. Finally, participants completed a comprehensive social questionnaire designed to assess a wide range of social dimensions, which were tested as predictors of alignment. Our results suggest that syntactic alignment is to some extent automatic, but socially mediated. We found an overall alignment effect across social conditions and independent of social perceptions. However, the degree of alignment was influenced by a number of factors, including the perceived standardness of the passage speaker's accent, participants' perceived similarity to the speaker, and participants' preference for compromise as a conflict management style. These findings are discussed in terms of theories of linguistic alignment and speech production.

A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels.

The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.

Calculation of selective filters of a device for primary analysis of speech signals

The amplitude-frequency responses of filters for primary analysis of speech signals, which have a low quality factor and a high rolloff factor in the high-frequency range, are calculated using the linear theory of speech production and psychoacoustic measurement data. The frequency resolution of the filter system for a sinusoidal signal is 40–200 Hz. The modulation-frequency resolution of amplitude- and frequency-modulated signals is 3–6 Hz. The aforementioned features of the calculated filters are close to the amplitudefrequency responses of biological auditory systems at the level of the eighth nerve.

Perceptuo-motor effects of response-distractor compatibility in speech: beyond phonemic identity.

Previous studies have found faster response times in a production task when a speaker perceives a distractor syllable that is identical to the syllable they are required to produce. No study has found such effects when a response and a distractor are not identical but share parameters below the level of the phoneme. Results from Experiment 1 show some evidence of a response-time effect of response-distractor voicing congruency. Experiment 2 showed a robust effect of articulator congruency: perceiving a distractor that has the same articulatory organ as that implicated in the planned motor response speeds up response times. These results necessitate a more direct and specific formulation of the perception-production link than warranted by previous experimental evidence. Implications for theories of speech production are also discussed.

Kenneth Noble Stevens

Kenneth Noble Stevens

Analysis and Recognition of Arabic Consonants Using Locus Equations

 Abstract—The acoustic measurement of articulation place for consonants and the acoustic measurement of the amount of coarticulation are two long-standing problems in phonetics. Previous work on consonant place of articulation, using articulatory-acoustic models, within the acoustic theory of speech production (Stevens, 1998), has found certain acoustic correlates of place, but the variability found in empirically-based studies has not provided an easy match to the theoretical predictions. This study is to analyze the precision with which locus equations determine the place of articulation for both Arabic plosives / q / (/ق /) and /? / (/ء/) and the two fricatives / ʕ / (/ع/) and / h / (/ه/), where these are preceded by the front vowel /u / and posterior vowel /i/ with respect the middle vowel /a/. The results helped to make the distinction (or classification) of these four phonemes by locus equation.

Integrating accounts of speech production: the devil is in the representational details

This commentary focuses on two key aspects of Hickok's proposal that distinguish it from other theories of speech production. Unlike many other accounts, auditory targets play a central and early role in speech production. This proposal also adopts a generally reductionist approach to the production of speech, relying almost exclusively on sensory and motor processes to represent sound structure. This eliminates various levels of phonological representation that play key roles in theories motivated by psycholinguistic and cognitive neuropsychological research. The general and specific issues raised by Hickok's approach are examined within two specific areas: the structure of sound representations and patterns of performance in “conduction aphasia.”

P 156. Deficient speech motor preparation in stuttering

Introduction Persistent developmental stuttering (PDS) is a speech fluency disorder that affects 1% of the population, predominantly males. Its etiology is unclear and likely multifactoral, with contributions from intrinsic factors pertaining to brain anatomy and neurophysiology, particularly abnormal right-hemispheric lateralization of blood flow in motor and premotor areas. Clinically, a major feature of stuttering is the paroxysmal inability to smoothly sequence articulatory gestures, resulting in frustraneous partial repetitions of the initial gestures. Objectives Attempting to further clarify the pathophysiology of the intermittent losses of motor control, we investigated changes in motor cortex excitability in the transition phase between articulatory gestures. We therefore studied speech-related modulation of excitability in the motor representation of the tongue. Materials and methods Thirteen fluent speakers and 13 adults who stutter were asked to build compound verbs with the verbal prefix “auf”. Single-pulse transcranial magnetic stimulation was applied over the primary motor cortex during the transition phase between a fixed labiodental articulatory configuration towards various articulatory configurations at five different latencies after transition onset. Bilateral electromyography was recorded from self-adhesive electrodes placed on the upper top of the tongue. Off-line, we extracted the motor evoked potential amplitudes and normalized these amplitudes to the individual baseline excitability during pronouncing of the prefix. Results Fluent-speaking control subjects showed a gradual increase of motor evoked potential amplitudes before the target articulatory gesture in the left motor cortex, and to a much lesser extent after stimulation of the right motor cortex. By contrast, stuttering adults lacked any premovement facilitation in the left motor cortex, but showed some premovement facilitation in the right motor cortex. Conclusion For decades theories of speech production postulate that the selection and the execution of speech units arise from facilitation of target units & inhibition of others. We present the first measurement of motor unit facilitation during speaking in real time. Excitability tuning of layer V pyramidal cell populations is quantified by MEP recordings from the tongue. Such data can guide the much needed integration of psycholinguistic and motor control approaches to speech production at a neurobiological level. Excitability tuning was absent in adults afflicted with PDS, indicating that the internal, speech-related signals triggering motor cortex facilitation were insufficient in strength or timing. This corroborates a disconnection hypothesis of speech-related brain areas in individuals suffering from PDS.

The coarticulation/invariance scale: Mutual information as a measure of coarticulation resistance, motor synergy, and articulatory invariance

Coarticulation and invariance are two topics at the center of theorizing about speech production and speech perception. In this paper, a quantitative scale is proposed that places coarticulation and invariance at the two ends of the scale. This scale is based on physical information flow in the articulatory signal, and uses Information Theory, especially the concept of mutual information, to quantify these central concepts of speech research. Mutual Information measures the amount of physical information shared across phonological units. In the proposed quantitative scale, coarticulation corresponds to greater and invariance to lesser information sharing. The measurement scale is tested by data from three languages: German, Catalan, and English. The relation between the proposed scale and several existing theories of coarticulation is discussed, and implications for existing theories of speech production and perception are presented.

On the interaction of sound with an annular aperture in a mean flow duct

An analysis is made of long wavelength sound interacting with a thin, rigid disc placed axisymmetrically across a circular cylindrical duct in the presence of a low Mach number mean flow. Vorticity produced at the edge of the disc causes an overall loss of acoustic energy, the effect of which is increased by the flow. Calculations are performed to derive a new analytical representation of the Rayleigh conductivity of the annular aperture between the disc and the duct wall, and a quasi-steady approximation is used to determine the unsteady drag on the disc. The results are used to estimate the corrected form of the conductivity in the presence of flow. This permits the Cummings–Fant ‘reduced complexity’ equation to be applied to study the absorption of acoustic energy at the disc [A. Cummings, American Institute of Aeronautics and Astronautics Journal 22 (1984) 786–792; G. Fant, Acoustic Theory of Speech Production, The Hague, Mouton, 1960].

Prediction and imitation in speech

It has been suggested that intra- and inter-speaker variability in speech are correlated. Interlocutors have been shown to converge on various phonetic dimensions. In addition, speakers imitate the phonetic properties of voices they are exposed to in shadowing, repetition, and even passive listening tasks. We review three theoretical accounts of speech imitation and convergence phenomena: (i) the Episodic Theory (ET) of speech perception and production (Goldinger, 1998); (ii) the Motor Theory (MT) of speech perception (Liberman and Whalen, 2000; Galantucci et al., 2006); (iii) Communication Accommodation Theory (CAT; Giles and Coupland, 1991; Giles et al., 1991). We argue that no account is able to explain all the available evidence. In particular, there is a need to integrate low-level, mechanistic accounts (like ET and MT), and higher-level accounts (like CAT). We propose that this is possible within the framework of an integrated theory of production and comprehension (Pickering and Garrod, 2013). Similarly to both ET and MT, this theory assumes parity between production and perception. Uniquely, however, it posits that listeners simulate speakers' utterances by computing forward-model predictions at many different levels, which are then compared to the incoming phonetic input. In our account phonetic imitation can be achieved via the same mechanism that is responsible for sensorimotor adaptation; i.e., the correction of prediction errors. In addition, the model assumes that the degree to which sensory prediction errors lead to motor adjustments is context-dependent. The notion of context subsumes both the preceding linguistic input and non-linguistic attributes of the situation (e.g., the speaker's and listener's social identities, their conversational roles, the listener's intention to imitate).