Reading and spontaneous speaking fundamental frequency of young Arabic men for Arabic and English languages: a comparative study

Speaking fundamental frequency (SFF), the average fundamental frequency (lowest frequency of a complex periodic sound) measured over the speaking time of a vocal or speech task, is a basic acoustic measure in clinical evaluation and treatment of voice disorders. Currently, there are few data on acoustic characteristics of different sociolinguistic groups, and no published data on the fundamental frequency characteristics of Arabic speech. The purpose of this study was to obtain preliminary data on the SFF characteristics of a group of normal speaking, young Arabic men. 15 native Arabic men (M age = 23.5 yr., SD=2.5) as participants received identical experimental treatment. Four speech samples were collected from each one, Arabic reading, Arabic spontaneous speech, English reading, and English spontaneous speech. Speaking samples, analyzed using the Computerized Speech Lab, showed no significant difference for mean SFF between language and type of speech and none for mean SFF between languages. A significant difference in the mean SFF was found between the types of speech. The SFF used during reading was significantly higher than that for spontaneous speech. Also Arabic men had higher SFF values than those previously reported for young men in other linguistic groups. SFF then might differ among linguistic, dialectical, and social groups and such data may provide clinicians information useful in evaluation and management of voice.     

Cortical asymmetries in speech perception: what's wrong,what's right and what's left?

Over the past 30 years hemispheric asymmetries in speech perception have been construed within a domain-general framework, according to which preferential processing of speech is due to left-lateralized, non-linguistic acoustic sensitivities. A prominent version of this argument holds that the left temporal lobe selectively processes rapid/temporal information in sound. Acoustically, this is a poor characterization of speech and there has been little empirical support for a left-hemisphere selectivity for these cues. In sharp contrast, the right temporal lobe is demonstrably sensitive to specific acoustic properties. We suggest that acoustic accounts of speech sensitivities need to be informed by the nature of the speech signal and that a simple domain-general vs. domain-specific dichotomy may be incorrect.     

Voice acoustical measurement of the severity of major depression

A number of empirical studies have documented the relationship between quantifiable and objective acoustical measures of voice and speech, and clinical subjective ratings of severity of Major Depression. To further explore this relationship, speech samples were extracted from videotape recordings of structured interviews made during the administration of the 17-item Hamilton Depression Rating Scale (HDRS; ). Pilot data were obtained from seven subjects (five males, two females) from videotapes that have been used to train expert raters on the administration and scoring of the HDRS. Several speech samples were isolated for each subject and processed to obtain the acoustic measurements. Acoustic measures were selected on the basis that they were correlated with HDRS ratings of symptom severity as seen under ideal voice recording conditions in previous studies. Our findings corroborate earlier reports that speaking rate is well correlated (negatively) with HDRS scores, with a strong correlation and nearly significant trend seen for the measure of pitch variability. A moderate pairwise correlation between percent pause time and HDRS score was also revealed, although this relationship was not statistically significant. The results from this cross-sectional study further demonstrate the ability of voice and speech signal analyses to objectively track severity of depression. In the present case, it is suggested that this relationship is robust enough to be found despite the less than ideal recording conditions and equipment used during the original videotape recording. Voice acoustical analyses may provide a powerful compliment to the standard clinical interview for depression. Use of such measures increases the range of techniques that are available to explore the neurobiological substrates of Major Depression, its treatment, and the dynamic interplay of the systems that govern the motor, cognitive, and emotional aspects of speech production.     

Temporal dimensions of consonant and vowel production: an acoustic and CT scan analysis of aphasic speech

This study explored a number of temporal (durational) parameters of consonant and vowel production in order to determine whether the speech production impairments of aphasics are the result of the same or different underlying mechanisms and in particular whether they implicate deficits that are primarily phonetic or phonological in nature. Detailed analyses of CT scan lesion data were also conducted to explore whether more specific neuroanatomical correlations could be made with speech production deficits. A series of acoustic analyses were conducted including voice-onset time, intrinsic and contrastive fricative duration, and intrinsic and contrastive vowel duration as produced by Broca's aphasics with anterior lesions (A patients), nonfluent aphasics with anterior and posterior lesions (AP patients), and fluent aphasics with posterior lesions (P patients). The constellation of impairments for the anterior aphasics including both the A and AP patients suggests that their disorder primarily reflects an inability to implement particular types of articulatory gestures or articulatory parameters rather than an inability to implement particular phonetic features. They display impairments in the implementation of laryngeal gestures for both consonant and vowel production. These patterns seem to relate to particular anatomical sites involving Broca's area, the anterior limb of the internal capsule, and the lowest motor cortex areas for larynx and tongue. The posterior patients also show evidence of subtle phonetic impairments suggesting that the neural instantiation of speech may require more extensive involvement, including the perisylvian area, than previously suggested.     

The Learning Signal in Perceptual Tuning of Speech: Bottom Up Versus Top-Down Information

Cognitive systems face a tension between stability and plasticity. The maintenance of long-term representations that reflect the global regularities of the environment is often at odds with pressure to flexibly adjust to short-term input regularities that may deviate from the norm. This tension is abundantly clear in speech communication when talkers with accents or dialects produce input that deviates from a listener's language community norms. Prior research demonstrates that when bottom-up acoustic information or top-down word knowledge is available to disambiguate speech input, there is short-term adaptive plasticity such that subsequent speech perception is shifted even in the absence of the disambiguating information. Although such effects are well-documented, it is not yet known whether bottom-up and top-down resolution of ambiguity may operate through common processes, or how these information sources may interact in guiding the adaptive plasticity of speech perception. The present study investigates the joint contributions of bottom-up information from the acoustic signal and top-down information from lexical knowledge in the adaptive plasticity of speech categorization according to short-term input regularities. The results implicate speech category activation, whether from top-down or bottom-up sources, in driving rapid adjustment of listeners' reliance on acoustic dimensions in speech categorization. Broadly, this pattern of perception is consistent with dynamic mapping of input to category representations that is flexibly tuned according to interactive processing accommodating both lexical knowledge and idiosyncrasies of the acoustic input.     

Phonetic variability and prosodic structure in mothers

Spontaneous speech acoustics are highly variable. Such variability may be problematic for infants relying on phonological form to solve the segmentation problem. In the present study, acoustic measures of vowel duration and a computer model of speech segmentation were used to evaluate the problem of phonetic variability for a rhythm-based speech segmentation strategy. The specific questions under study were (1) whether or not mothers realized disyllabic vowel duration patterns consistently in spontaneous infant-directed speech, and (2) whether or not these patterns were distinctive enough in the context of an utterance to provide a useful cue for speech segmentation. Data from four English-speaking mothers indicated that the trochaic-like duration pattern may interact with phrase-position and with grammatical category, but when the resulting patterns are consistent, they provide useful segmentation cues for spontaneous infant-directed speech.     

Temporally nonadjacent nonlinguistic sounds affect speech categorization

Speech perception is an ecologically important example of the highly context-dependent nature of perception; adjacent speech, and even nonspeech, sounds influence how listeners categorize speech. Some theories emphasize linguistic or articulation-based processes in speech-elicited context effects and peripheral (cochlear) auditory perceptual interactions in non-speech-elicited context effects. The present studies challenge this division. Results of three experiments indicate that acoustic histories composed of sine-wave tones drawn from spectral distributions with different mean frequencies robustly affect speech categorization. These context effects were observed even when the acoustic context temporally adjacent to the speech stimulus was held constant and when more than a second of silence or multiple intervening sounds separated the nonlinguistic acoustic context and speech targets. These experiments indicate that speech categorization is sensitive to statistical distributions of spectral information, even if the distributions are composed of nonlinguistic elements. Acoustic context need be neither linguistic nor local to influence speech perception.     

Moving to the speed of sound: context modulation of the effect of acoustic properties of speech

Suprasegmental acoustic patterns in speech can convey meaningful information and affect listeners' interpretation in various ways, including through systematic analog mapping of message-relevant information onto prosody. We examined whether the effect of analog acoustic variation is governed by the acoustic properties themselves. For example, fast speech may always prime the concept of speed or a faster response. Alternatively, the effect may be modulated by the context-dependent interpretation of those properties; the effect of rate may depend on how listeners construe its meaning in the immediate linguistic or communicative context. In two experiments, participants read short scenarios that implied, or did not imply, urgency. Scenarios were followed by recorded instructions, spoken at varying rates. The results show that speech rate had an effect on listeners' response speed; however, this effect was modulated by discourse context. Speech rate affected response speed following contexts that emphasized speed, but not without such contextual information.     

Self-Report Differentiation of Anxiety and Depression in a Mood Disorders Sample

Several lines of research suggest there is considerable overlap between anxiety and depression and that it is difficult to distinguish between these two constructs. However, a few studies utilizing factor analytic procedures have provided evidence that anxiety and depression can be differentiated when measures of these constructs are considered at the item level. In addition, there is some evidence that differentiation can be accomplished in samples experiencing high levels of anxiety (i.e., a clinically anxious sample; B. J. Cox, R. P. Swinson, L. Kuch, & J. Reichman, 1993). In the present study, this research strategy was extended to a sample of patients with high levels of depressed mood (i.e., a mood disorders sample; N = 378). Their responses to widely used measures of depression (i.e., Beck Depression Inventory; A. T. Beck, C. H. Ward, M. Mendelson, J. Mock, & J. Erbaugh, 1961) and anxiety (i.e., Spielberger State-Trait Anxiety Inventory—State subscale; C. D. Spielberger, R. L. Gorsuch, & R. E. Lushene, 1970) were entered into a principal-components analysis with oblique rotation. A 4-factor solution was retained. This solution was comprised of factors representing anxiety, anxiety absent (a reverse scored factor), cognitive symptoms of depression, and somatic/vegetative symptoms of depression. These findings indicated that anxiety and depression, as emotional states, can be differentiated within a mood disorders sample, using existing popular self-report measures. The clinical and research implications of these findings are briefly discussed.     

Perceptual normalization of vowels produced by sinusoidal voices

When listeners hear a sinusoidal replica of a sentence, they perceive linguistic properties despite the absence of short-time acoustic components typical of vocal signals. Is this accomplished by a postperceptual strategy that accommodates the anomalous acoustic pattern ad hoc, or is a sinusoidal sentence understood by the ordinary means of speech perception? If listeners treat sinusoidal signals as speech signals however unlike speech they may be, then perception should exhibit the commonplace sensitivity to the dimensions of the originating vocal tract. The present study, employing sinusoidal signals, raised this issue by testing the identification of target /bVt/, or b-vowel-t, syllables occurring in sentences that differed in the range of frequency variation of their component tones. Vowel quality of target syllables was influenced by this acoustic correlate of vocal-tract scale, implying that the perception of these nonvocal signals includes a process of vocal-tract scale, implying that the perception of these nonvocal signals includes a process of vocal-tract normalization. Converging evidence suggests that the perception of sinusoidal vowels depends on the relation among component tones and not on the phonetic likeness of each tone in isolation. The findings support the general claim that sinusoidal replicas of natural speech signals are perceptible phonetically because they preserve time-varying information present in natural signals.     

Perception of dynamic acoustic patterns by an individual with unilateral verbal auditory agnosia

Previous studies have found that subjects diagnosed with verbal auditory agnosia (VAA) from bilateral brain lesions may experience difficulties at the prephonemic level of acoustic processing. In this case study, we administered a series of speech and nonspeech discrimination tests to an individual with unilateral VAA as a result of left-temporal-lobe damage. The results indicated that the subject's ability to perceive steady-state acoustic stimuli was relatively intact but his ability to perceive dynamic stimuli was drastically reduced. We conclude that this particular aspect of acoustic processing may be a major contributing factor that disables speech perception in subjects with unilateral VAA.     

Reading instruction and remediation with the aid of computer speech

In this paper, we describe the application of new computer and speech synthesis technologies for reading instruction. Stories are presented on the computer screen, and readers may designate words or parts of words that they cannot read for immediate speech feedback. The important contingency between speech sounds and their corresponding letter patterns is emphasized by displaying the letter patterns in reverse video as they are spoken. Speech feedback is provided by an advanced text-to-speech synthesizer (DECtalk). Intelligibility data are presented, showing that DECtalk can be understood almost as well as natural human speech by both normal adults and reading disabled children. Preliminary data from 26 disabled readers indicate that there are significant benefits of speech feedback for reading comprehension and word recognition, and that children enjoy reading with the system.     

Neuromagnetic evidence for a featural distinction of English consonants: sensor- and source-space data

Speech sounds can be classified on the basis of their underlying articulators or on the basis of the acoustic characteristics resulting from particular articulatory positions. Research in speech perception suggests that distinctive features are based on both articulatory and acoustic information. In recent years, neuroelectric and neuromagnetic investigations provided evidence for the brain's early sensitivity to distinctive features and their acoustic consequences, particularly for place of articulation distinctions. Here, we compare English consonants in a Mismatch Field design across two broad and distinct places of articulation - labial and coronal - and provide further evidence that early evoked auditory responses are sensitive to these features. We further add to the findings of asymmetric consonant processing, although we do not find support for coronal underspecification. Labial glides (Experiment 1) and fricatives (Experiment 2) elicited larger Mismatch responses than their coronal counterparts. Interestingly, their M100 dipoles differed along the anterior/posterior dimension in the auditory cortex that has previously been found to spatially reflect place of articulation differences. Our results are discussed with respect to acoustic and articulatory bases of featural speech sound classifications and with respect to a model that maps distinctive phonetic features onto long-term representations of speech sounds.     

Adaptation of speech by nonspeech: evidence for complex acoustic cue detectors

Three selective adaptation experiments were run, using nonspeech stimuli (music and noise) to adapt speech continua ([ba]-[wa] and [cha]-[sha]). The adaptors caused significant phoneme boundary shifts on the speech continua only when they matched in periodicity: Music stimuli adapted [ba]-[wa], whereas noise stimuli adapted [cha]-[sha]. However, such effects occurred even when the adaptors and test continua did not match in other simple acoustic cues (rise time or consonant duration). Spectral overlap of adaptors and test items was also found to be unnecessary for adaptation. The data support the existence of auditory processors sensitive to complex acoustic cues, as well as units that respond to more abstract properties. The latter are probably at a level previously thought to be phonetic. Asymmetrical adaptation was observed, arguing against an opponent-process arrangement of these units. A two-level acoustic model of the speech perception process is offered to account for the data.     

Difficulties in auditory organization as a cause of reading backwardness? An auditory neuroscience perspective

Over 30 years ago, it was suggested that difficulties in the ‘auditory organization’ of word forms in the mental lexicon might cause reading difficulties. It was proposed that children used parameters such as rhyme and alliteration to organize word forms in the mental lexicon by acoustic similarity, and that such organization was impaired in developmental dyslexia. This literature was based on an ‘oddity’ measure of children's sensitivity to rhyme (e.g. wood, book, good) and alliteration (e.g. sun, sock, rag). The ‘oddity’ task revealed that children with dyslexia were significantly poorer at identifying the ‘odd word out’ than younger children without reading difficulties. Here we apply a novel modelling approach drawn from auditory neuroscience to study the possible sensory basis of the auditory organization of rhyming and non‐rhyming words by children. We utilize a novel Spectral‐Amplitude Modulation Phase Hierarchy (S‐AMPH) approach to analysing the spectro‐temporal structure of rhyming and non‐rhyming words, aiming to illuminate the potential acoustic cues used by children as a basis for phonological organization. The S‐AMPH model assumes that speech encoding depends on neuronal oscillatory entrainment to the amplitude modulation (AM) hierarchy in speech. Our results suggest that phonological similarity between rhyming words in the oddity task depends crucially on slow (delta band) modulations in the speech envelope. Contrary to linguistic assumptions, therefore, auditory organization by children may not depend on phonemic information for this task. Linguistically, it is assumed that ‘book’ does not rhyme with ‘wood’ and ‘good’ because the final phoneme differs. However, our auditory analysis suggests that the acoustic cues to this phonological dissimilarity depend primarily on the slower amplitude modulations in the speech envelope, thought to carry prosodic information. Therefore, the oddity task may help in detecting reading difficulties because phonological similarity judgements about rhyme reflect sensitivity to slow amplitude modulation patterns. Slower amplitude modulations are known to be detected less efficiently by children with dyslexia.     

Infants’ listening in multitalker environments: Effect of the number of background talkers

Infants are often spoken to in the presence of background sounds, including speech from other talkers. In the present study, we compared 5- and 8.5-month-olds’ abilities to recognize their own names in the context of three different types of background speech: that of a single talker, multitalker babble, and that of a single talker played backward. Infants recognized their names at a 10-dB signal-to-noise ratio in the multiple-voice condition but not in the single-voice (nonreversed) condition, a pattern opposite to that of typical adult performance. Infants similarly failed to recognize their names when the background talker’s voice was reversed—that is, unintelligible, but with speech-like acoustic properties. These data suggest that infants may have difficulty segregating the components of different speech streams when those streams are acoustically too similar. Alternatively, infants’ attention may be drawn to the time-varying acoustic properties associated with a single talker’s speech, causing difficulties when a single talker is the competing sound.     

Perception of spasmodic dysphonia speech in background noise

The purpose of this investigation was to judge whether the Lombard effect, a characteristic change in the acoustical properties of speech produced in noise, existed in adductor spasmodic dysphonia speech, and if so, whether the effect added to or detracted from speaker intelligibility. Intelligibility, as described by Duffy, is the extent to which the acoustic signal produced by a speaker is understood by a listener based on the auditory signal alone. Four speakers with adductor spasmodic dysphonia provided speech samples consisting of low probability sentences from the Speech Perception in Noise test to use as stimuli. The speakers were first tape-recorded as they read the sentences in a quiet speaking condition and were later tape-recorded as they read the same sentences while exposed to background noise. The listeners used as subjects in this study were 50 undergraduate university students. The results of the statistical analysis indicated a significant difference between the intelligibility of the speech recorded in the quiet versus noise conditions (F(1,49) = 57.80, p < or = .001). It was concluded that a deleterious Lombard effect existed for the adductor spasmodic dysphonia speaker group, with the premise that the activation of a Lombard effect in such patients may detract from their overall speech intelligibility.     

Differential diagnosis between apraxia and dysarthria based on acoustic analysis

Acoustic analysis provides objective quantitative measures of speech that enable a comprehensive and accurate understanding of motor disorders and complement the traditional measures. This paper aims to distinguish between normal and pathological speech, more specifically between apraxia of speech and spastic dysarthria in native Spanish speaking patients using acoustic parameters. Participants (4 aphasic with apraxia of speech, 4 with spastic dysarthria, and 15 without speech disorders) performed three different tasks: repeating the syllable sequence [pa-ta-ka], repeating the isolated syllable [pa] and repeating the vowel sequence [i-u]. The results showed that the normative values of motor control, in general, coincide with those obtained in previous research on native English speakers. They also show that damage to motor control processes results in a decrease in the rate of alternating and sequential movements and an increase in the inter-syllabic time for both types of movements. A subset of the acoustic parameters analyzed, those that measure motor planning processes, enable differentiation between normal population and apraxic and dysarthric patients, and between the latter. The differences between the pathological groups support the distinction between motor planning and motor programming as described by van der Merwe's model of sensorimotor processing (1997).