Speech Apparatus Research Articles

A Case of Frontotemporal Lobar Degeneration with Progressive Dysarthria

We investigated the evolution of the neurological and neuropsychological characteristics in a right-handed woman who was 53-years-old at the onset and who showed personality changes and behavioral disorders accompanied by progressive dysarthria. She had hypernasality and a slow rate of speech with distorted consonants and vowels, which progressed as motor disturbances affecting her speech apparatus increased; finally, she became mute two years post onset. Her dysarthria due to bilateral voluntary facio-velo-linguo-pharyngeal paralysis accompanied with automatic-voluntary dissociation fit the description of anterior opercular syndrome. She showed personality changes and behavioral abnormalities from the initial stage of the disease, as is generally observed in frontotemporal degeneration (FTD), and her magnetic resonance image showed progressive atrophy in the frontotemporal lobes; thus, she was clinically diagnosed with FTLD. This patient’s symptoms suggest that FTLD, including bilateral anterior operculum degeneration, causes progressive pseudobulbar paretic dysarthria accompanied by clinical symptoms of FTD, which raises the possibility of a new clinical subtype in the FTLD spectrum.

Vocal tract length development during the first two decades of life: A magnetic resonance imaging study

As the vocal tract length (VTL) increases more than twofold from infancy to adulthood, its geometric proportions change. This study assesses the developmental changes of the various hard and soft tissue structures in the vicinity of the vocal tract (VT), and evaluates the relational growth of the various structures with VTL. Magnetic resonance images from 327 cases, ages birth to age 20, were used to secure quantitative measurements of the various soft, cartilaginous and bony structures in the oral and pharyngeal regions using established procedures [Vorperian et al. (1999), (2005)]. Structures measured include: lip thickness, hard- and soft-palate length, tongue length, naso-oro-pharyngeal length, mandibular length and depth, and distance of the hyoid bone and larynx from the posterior nasal spine. Findings indicate: (a) ongoing growth of all oral and pharyngeal structures with changes in growth rate as a function of age; (b) a strong interdependency between structure orientation and its growth curve; and (c) developmental changes in the relational growth of the different VT structures with VTL. Findings provide normative data on the anatomic changes of the supra-laryngeal speech apparatus, and can be used to model the development of the VT. [Work supported by NIH-NIDCD Grants R03-DC4362 R01-DC006282, and NIH-NICHHD P30-HK03352.]

Speech information processing method and apparatus and storage medium

A speech information processing apparatus which sets the duration of phonological series with accuracy, and sets a natural phoneme duration in accordance with phonemic/linguistic environment. For this purpose, the duration of a predetermined unit of phonological series is obtained based on a duration model for an entire segment. Then, duration of each of phonemes constructing the phonological series is obtained based on a duration model for a partial segment (S 303 ). Then, duration of each phoneme is set based on the duration of the phonological series and the duration of each phoneme.

Client-server speech processing system, apparatus, method, and storage medium

The system implements high-accuracy speech recognition while suppressing the amount of data transfer between the client and server. For this purpose, the client compression-encodes speech parameters by a speech processing unit, and sends the compression-encoded speech parameters to the server. The server receives the compression-encoded speech parameters, a speech processing unit makes speech recognition of the compression-encoded speech parameters, and sends information corresponding to the speech recognition result to the client.

On the complex nature of speech kinematics

Studying kinematic behavior in speech production is an indispensable and fruitful methodology in order to describe for instance phonemic contrasts, allophonic variations, prosodic effects in articulatory movements. More intriguingly, it is also interpreted with respect to its underlying control mechanisms. Several interpretations have been borrowed from motor control studies of arm, eye, and limb movements. They do either explain kinematics with respect to a fine tuned control by the Central Nervous System (CNS) or they take into account a combination of influences arising from motor control strategies at the CNS level and from the complex physical properties of the peripheral speech apparatus. We assume that the latter is more realistic and ecological. The aims of this article are: first, to show, via a literature review related to the so called '1/3 power law' in human arm motor control, that this debate is of first importance in human motor control research in general. Second, to study a number of speech specific examples offering a fruitful framework to address this issue. However, it is also suggested that speech motor control differs from general motor control principles in the sense that it uses specific physical properties such as vocal tract limitations, aerodynamics and biomechanics in order to produce the relevant sounds. Third, experimental and modelling results are described supporting the idea that the three properties are crucial in shaping speech kinematics for selected speech phenomena. Hence, caution should be taken when interpreting kinematic results based on experimental data alone.

Review

Background : This work was motivated by recent attempts at explaining apraxia of speech as a general motor disorder which involves both speech and nonspeech movements (Ballard, Granier, & Robin, 2000). It also relates to some more recent theoretical accounts of the diagnostic value of nonspeech tasks, which postulate that such tasks may help to isolate single motor components and examine their individual contributions to a complex motor speech impairment (e.g., Folkins et al., 1995; Robin, Solomon, Moon, & Folkins, 1997). These approaches are implicitly based on a model which assumes that motor control of the organs implicated in speaking is independent of the particular motor task that is imposed on them. Aims : Two alternative models are discussed: a task-independent model of motor control, which postulates a universal sensory-motor system controlling all motor functions of the speech apparatus, irrespective of their purpose, and a task-dependent model, which postulates different sensory-motor control systems for vegetative functions, emotional expression, and speech. The motor subsystems distinguished in the task-dependent model are considered separate in the sense that (1) they involve distinct sensory-motor patterns, (2) they are based on distinct and specialised neural circuitries, and (3) their impairments through brain lesions are dissociated from each other and from impairments of the nonspeech voluntary motor functions of the same musculature. Main Contribution : Evidence for the task-dependent model is provided in three major sections: a section on vegetative motor functions, a section on emotional expressive motor functions, and a section on voluntary nonspeech motor activities. In each section, clinical and experimental dissociations between speech and nonspeech tasks are reviewed and the physiological and neuro-anatomical underpinnings of these observations are discussed. In a general discussion, the nature of speech as a learned motor skill and the relation of speech motor control to an auditory reference frame are highlighted. Conclusions : It is claimed that both the dysarthrias and apraxia of speech should be considered disorders of a sensory-motor system specialised for speaking. Impairments of speech and nonspeech movements should be kept separate.

Concatenation of speech segments by use of a speech synthesizer

In a speech synthesizer apparatus, a weighting coefficient training controller calculates acoustic distances in second acoustic feature parameters between one target phoneme from the same phoneme and the phoneme candidates other than the target phoneme based on first acoustic feature parameters and prosodic feature parameters, and determines weighting coefficient vectors for respective target phonemes defining degrees of contribution to the second acoustic feature parameters for respective phoneme candidates by executing a predetermined statistical analysis therefor. Then, a speech unit selector searches for a combination of phoneme candidates which correspond to a phoneme sequence of an input sentence and which minimizes a cost including a target cost representing approximate costs between a target phoneme and the phoneme candidates and a concatenation cost representing approximate costs between two phoneme candidates to be adjacently concatenated, and outputs index information on the searched out combination of phoneme candidates. Further, a speech synthesizer synthesizes a speech signal corresponding to the input phoneme sequence by sequentially reading out speech segments of speech waveform signals corresponding to the index information and concatenating the read speech segments of the speech waveform signals.

About Hens and Eggs-Perception and Action, Ecology and Neuroscience:A Reply to Michaels (2000)

Michaels (2000) suggested that vision for perception can and should be separated from vision for action. Methodological, logical, and empirical grounds for this conclusion are critically discussed. Data are presented that perception and action are not 2 different entities, and therefore, they can neither follow each other (the view that Michaels rejects) nor run in parallel (the view she appears to accept). They are 2 aspects of the same reality of behavioral control. Telling about perception is not perception itself; brains disconnected from an efficient speech apparatus may be able to extract environmental information. What is often referred to as dissociation between perception and action is not a fiction; rather, such cases indicate important distinctions between different classes of behavioral control. All classes, however, involve both perception and action.

Multi-dialect speech recognition method and apparatus

Apparatus and method for improving the speed an accuracy of recognition of speech dialects, or speech tansferred via dissimilar channels is described. The invention provides multiple models tailored to specific segments or dialects, and/or speech channels, of the population. However, there is not a proportional increase in recognition time or computing power or computing resources needed. Probability density functions for the acoustic descriptors are provided which are shared among the various models. Since there is a common pool of probability density functions which are mapped or pointed to for the different acoustic descriptors for each different dialect or speech channel model, the memory requirements for the speech recognition apparatus and method are significantly reduced. Each model is comprised of triphonemes which are modelled by discrete probability distribution functions forming hidden Markov models or statistical word models. Any one probability density function is assigned or mapped to many different triphonemes in many different dialects or different models. The invention provides for an automatic selection of the best model in real time wherein the best fit is determined by a voting process.

Assessment of dysarthric speech: a case for a combined perceptual and physiological approach

Traditionally, the assessment of dysarthric speech has mainly involved the use of perceptual evaluation measures. The inherent inadequacies of this method of assessment have resulted in the development of a range of instrumental assessment techniques to provide more objective analyses of the underlying physiological impairments of the speech apparatus in individuals with a dysarthric speech disturbance. The aim of the current study was to highlight the importance of a combined approach to the assessment of dysarthria with reference to two case studies of individuals with dysarthric speech: a 32-year-old adult who suffered a severe closed head injury and a nine-year-old child who experienced a cerebrovascular accident involving the basilar artery. Each subject was assessed using a battery of perceptual and physiological techniques. The results for each case indicated that instrumental measures were effective in identifying the severity and nature of the underlying physiological impairments in the various subsystems of the speech mechanism, and highlighted the importance of verifying perceptual judgements with instrumental measures. The results are discussed in relation to the value of a combined perceptual and physiological approach in determining an accurate evaluation and diagnosis of the dysarthric speech impairment and in defining appropriate treatment goals.

Method and apparatus for efficient multiband celp wideband speech and music coding and decoding

A method of digitally compressing speech and music by use of multiple band ("multiband") fixed excitations stored in codebooks. The use of multiband fixed excitations, along with a coupling method for interconnecting the excitation codebooks and adaptive codebooks and for generating the composite excitation signal, improve the long-term and short-term prediction, and the use of voice-music classification allows the coding structure to be adapted to the statistical character of the audio signal.

A latent trait approach to the development of persistent stuttering.

The premise that stuttering disorders develop according to the orthogenetic principle, preceding in a continuous, unilinear fashion from a state of relative lack of differentiation to a state of increasing differentiation and hierarchic integration, was examined. Responses to Woolf's Perceptions of Stuttering Inventory of 87 individuals who stutter were analyzed using a Rasch 1980 latent trait model for dichotomously scored data. Analyses of responses indicated struggle, avoidance, and expectation through the development of stuttering that became increasingly articulated, integrated, stable, and yet responsive to environmental changes. Four stages of development were noted: Stage I was characterized by the expectation of interruptions in the flow of speech, the addition of unnecessary sounds, and general body tension. Stage II was typified by distinctions between troublesome and not so troublesome words and sounds and between the speaker and various audiences and contexts for speaking. In Stage III, speech control decreased despite more focused and complex efforts to control the environment and the speech apparatus. Stage IV was characterized by automatic scanning of all speech, increasingly uncontrolled body movements, and attempts to produce fluent speech by way of comprehensive changes to sound, rhythm, and pitch. Follow-up of 29 respondents suggested the latent struggle was generally stable over time.

Speech synthesis apparatus and method for synthesizing speech from a character series comprising a text and pitch information

A speech synthesis method and apparatus for synthesizing speech from a character series comprising a text and pitch information. The apparatus includes a parameter generator for generating power spectrum envelopes as parameters of a speech waveform to be synthesized representing the input text in accordance with the input character series. The apparatus also includes a pitch waveform generator for generating pitch waveforms whose period equals the pitch specified by the pitch information. The pitch waveform generator generates the pitch waveforms from the input pitch information and the power spectrum envelopes generated by the parameter generator. Also provided is a speech waveform output device for outputting the speech waveform obtained by connecting the generated pitch waveforms.

Method and apparatus for processing speech

The speech processing apparatus and method includes a microphone, an analyzer, a selector, and a memory. The microphone converts input speech into an electrical signal representing speech data. The analyzer converts the speech data into non-linear frequency converted speech data in accordance with a non-linear frequency conversion. The selector selects a coefficient of the non-linear frequency conversion suitable for each of the phonemes or frames of the speech. The memory stores the speech data.

Speech communication apparatus having an echo canceler

The invention is directed to an apparatus for speech communication that includes an echo canceler (3) for canceling an acoustic echo component input from a hands-free speech loudspeaker (13) to a microphone (14). The echo canceler (30) is provided with a volume control (36) for variably controlling the volume of a received speech signal, an amplitude limiter (35) for limiting the amplitude of an output signal from the volume control (36), an echo canceler (32, 32) for estimating a pseudo echo signal from an output from the amplitude limiter and subtracting the estimated pseudo echo signal from the transmitted speech signal input from the microphone (14), and a nonlinear filter (34) for processing an output from the echo canceler, thereby limiting the amplitude level of the received speech signal to a predetermined level or less. Accordingly, even if a received speech signal having a high received speech signal level is input to the echo canceler, the received speech is not distorted, and an acoustic echo can be sufficiently canceled by the echo canceler.

Speech coding parameter smoothing method

A decoding method and apparatus for speech coding systems which takes into account the fact that the human auditory system is sensitive to changes in signal characteristics. For example, a sustained distortion of the spectral characteristic of reconstructed speech is usually less perceptible than an objectively smaller distortion which changes as a function of time. This property of the auditory system is advantageously exploited in the design of a speech coding system receiver in accordance with the present invention, by selecting the sequence of decoded speech parameter values on a perceptual basis. Illustratively, the sequence of decoded speech parameter values is selected so as to describe a smooth path through the sequence of Voronoi regions. The distance between successive parameter values is advantageously minimized, under the constraint that the resultant parameter values fall within, or nearly within, the appropriate Voronoi regions. In this manner, a smoother trajectory will result, thereby enabling the receiver to produce a perceptually superior reconstructed speech signal.

Electroacoustic speech intelligibility enhancement method and apparatus

One or more electronically-controllable blocks rapidly vary the device's acoustic gain. The electronically-controllable blocks variably amplify or attenuate the incoming signal, controlled by the output signals of one or more level detectors. The input signals of the level detectors are representative of the acoustic input signal being processed by the apparatus and produce controlling signals in response to detection of sound pressure levels within a predetermined range. Multi-level compression is achieved when a first level detector in conjunction with an electronically-controllable amplifier block compresses signals which have an input sound pressure level above a compressor lower bound α and below a compressor upper bound β, and when a second level detector in conjunction with either an electronically-controllable amplifier or attenuator block compresses signals which have a sound pressure level above a second compressor lower bound γ. For input signals of sound pressure level below α or between β and γ, amplification is linear. Input amplifier saturation is prevented by having the second level detector alter the transmission of an electronically-controlled attenuator placed prior to the first stage of amplification. Single-level compression is provided by independent detection and utilization of compression ranges α to β and over γ.

Instability of voice in adolescence: Pathologic condition or normal developmental variation?

Objective: Pediatricians often send adolescents with dysphonia to the otorhinolaryngologist's office to find the reason for their hoarseness. The aim of this study was to identify the main characteristics of adolescent voice and to determine which characteristic (variable of voice analysis) can distinguish normal variations of voice development from pathologic disorders. Study design: On the basis of history, indirect laryngoscopy, and stroboscopy, 51 adolescents (22 boys, 29 girls) from age 10 to 17 years were divided into four subgroups: candidates for singing lessons without voice problems, subjects with mutation voice disorders, subjects with functional dysphonia, and subjects with vocal cord nodules. Voice analysis by Multi-Dimensional Voice Program (Kay Elemetrics) evaluated the fundamental frequency, the variability of pitch and amplitude (loudness), and the presence of noise in the analyzed voice sample of each of the subjects. Data were analyzed with the SPSS+/PC Statistical Program. Results: All mean values of variables that describe variability of pitch and amplitude were abnormal in boys and in girls, with greater abnormality among boys. The variability of loudness and specifically the variability of pitch were abnormal in a majority of subjects. A significant negative correlation between age and fundamental frequency was stated in boys only and between age and variability of amplitude in girls only. Variables that express variability of pitch and amplitude correlated positively between themselves. No significant differences were found between the first subgroup (candidates for singing lessons), which represented a normal population, and the other three subgroups (subjects with mutational disorders, functional dysphonia, and vocal cord nodules). In addition, no significant differences were found between the first three subgroups (subjects without voice problems and subjects with functional voice disorders) and the fourth subgroup (subjects with vocal cord nodules: organic lesion of laryngeal mucosa). Conclusions: According to this study, the main characteristic of adolescent voice is the instability of amplitude (loudness) and specifically the instability of pitch. Female voices appear more stable than male voices. No single variable of performed voice analysis can distinguish normal variation of voice development from pathologic disorders. The reason for this instability can be attributed to more gradual adaptation of the afferent and efferent nervous control to the rapid growth of the phonatory, respiratory, and resonatory organs. In the growing speech apparatus, optimal phonatory patterns can be created; therefore adolescence is an ideal period for treatment of functional voice disorders. (J Pediatr 1997;130:185-90)

Differences in speaker’s articulatory space: Their contribution to vowel gesture and acoustic pattern

The view that individual speaker characteristics reflect morphological and functional differences in the speech apparatus has been accepted as self-evident despite the lack of convincing empirical data. A recent study on the issue of individual differences based on x-ray microbeam data from ten American English and ten Japanese speakers (five males and five females in each group) has pointed to a significance of morphology in accounting for speaker characteristics of vowel gesture. The midsagittal form of a speaker’s orofacial structure was parametrized by several landmarks on x-ray scan images. A few points and lines were chosen to form a quadrilateral framework so that they define a geometrical ‘‘articulatory space’’ where articulation of the tongue–jaw complex takes place. Pellet data for vowels were mapped onto speaker’s articulatory space to observe the effect of morphological difference on vowel articulation. Preliminary results have shown the extent of morphological variation of the speech apparatus and adaptability of vowel gesture to different forms of the space. The aspect ratio of the articulatory space was judged as the primary causal factor of articulatory variation. Acoustic manifestation and perceptual contribution of the variation will be discussed from a viewpoint of auditory-articulatory linkage.

Speech bandwidth extension method and apparatus

A speech bandwidth extension method and apparatus analyzes narrowband speech sampled at 8 kHz using LPC analysis to determine its spectral shape and inverse filtering to extract its excitation signal. The excitation signal is interpolated to a sampling rate of 16 kHz and analyzed for pitch control and power level. A white noise generated wideband signal is then filtered to provide a synthesized wideband excitation signal. The narrowband shape is determined and compared to templates in respective vector quantizer codebooks, to select respective highband shape and gain. The synthesized wideband excitation signal is then filtered to provide a highband signal which is, in turn, added to the narrowband signal, interpolated to the 16 kHz sample rate, to produce an artificial wideband signal. The apparatus may be implemented on a digital signal processor chip.