American English Phonemes Research Articles

Articulatory Range of Movement in Individuals With Dysarthria Secondary to Amyotrophic Lateral Sclerosis.

The current study examined overall articulatory range of movement (ROM) in individuals with amyotrophic lateral sclerosis (ALS). Differential involvement of articulators was also tested using articulatory working space in individuals with varying degrees of dysarthria severity and in typically aging individuals. A strong association between overall articulatory ROM and severity measures among individuals with ALS was hypothesized. In addition, it was hypothesized that differential involvement of articulators would be detected using overall articulatory ROM measures. Twenty-two speakers with dysarthria secondary to ALS and 22 typically aging speakers participated. Speech intelligibility and speaking rate were used as indices of severity. Movement range and overall articulatory working space area (convex hull) of the tongue, lower lip, and jaw were each measured by electromagnetic articulography while the speakers produced the Rainbow Passage. Tongue convex hull size was significantly correlated with both indices of severity. A significant interaction between articulators and groups was observed. Individuals with severe dysarthria had reduced tongue convex hull size and exaggerated lower lip convex hull size. ROM in the anterior-posterior dimension showed a more notable differential involvement pattern than ROM in the superior-inferior dimension. Results in the area under a receiver operating characteristic curve analysis revealed group-specific ROM sensitivity. The findings indicate that tongue ROM is reduced in individuals with more severe dysarthria when estimated using a standardized paragraph containing all American English phonemes. The articulatory working space measure could be useful for estimating speech dysfunction in ALS. ROM of the tongue decreases, but ROM of the lower lip and jaw each increase in individuals with severe dysarthria. Differential involvement of the articulators in the anterior-posterior dimension needs to be further investigated.

Acoustic Analysis of Intensive Language Exposure on Second Language Learners’ Cognitive Perception Pattern of American English Phonemes

This paper attempts to quantify the perception of tense vowel /i/ and lax vowel /I/ in American English by native speakers and Chinese learners and testify if Chinese learners also rely more on acoustic features than duration to differentiate the minimal pair /i/-/I/ in the phonetic system of American English. Based on the related phonetic studies in second language learners (SLLs), the perceptual assimilation model (PAM) and the speech learning model (SLM) were adopted to discuss the effect of intensive language exposures on the perception of English phonemes among Chinese learners. To quantify the effects of the ILE on the perception pattern of the SLLs, two English phonetic continuums were constructed for a tense-lax vowel contrast /i/ and /I/. Then, three groups of subjects, involving 60 English major students and 10 native speakers, received two identification tests and one discrimination test. The test results reveal that the native speakers and the SLLs relied on different acoustic cues to distinguish between /i/ and /I/. The former mainly depended on formant distribution, while the latter on duration. Besides, it is also concluded that the ILE enabled the SLLs to develop a similar perception pattern to that of the native speakers. The research sheds new light on the acquisition of second language among Chinese learners.

Multidimensional Approach to the Development of a Mandarin Chinese-Oriented Sound Test.

Because the Ling six-sound test is based on American English phonemes, it can yield unreliable results when administered to non-English speakers. In this study, we aimed to improve specifically the diagnostic palette for Mandarin Chinese users by developing an adapted version of the Ling six-sound test. To determine the set of testing sounds, we performed an exhaustive acoustic and statistical analysis in which we considered not only the general acoustic properties but also the order of acquisition and the inter- and intraspeaker variability. Six phonemes (/u, ə, a, i, tɕh, s/) were selected as the testing items for the Mandarin Chinese sound test because these sounds exhibit a highly compartmentalized frequency specificity, spanning the entire Chinese speech spectrum, as well as a relatively low articulatory variability and can be acquired fairly early. Through adopting language-dependent modifications, caregivers and professionals should have a more adequate tool to monitor children's auditory access to the full range of Mandarin speech sounds.

Shannon entropy predicts the sonority status of natural classes in English

Speech sounds tend to co-occur in the speech stream according to specific combinatory patterns predicted from their sonority status [Parker, S. G. (2002). Quantifying the sonority hierarchy. Unpublished doctoral dissertation, University of Massachusetts, Amherst, MA]. This study introduces a measure of spectral complexity, inspired by Shannon entropy, that ranks American English phonemes into a minimal version of the sonority hierarchy: vowels > approximants > nasals > fricatives > affricates > stops. Spectral complexity for every consonant and vowel in the TIMIT database was calculated by first parsing the phonemes into 20-ms segments and computing an FFT. For each short-term FFT, Shannon entropy was computed using the distribution of relative amplitudes (dB) across frequency. Average entropy across the FFTs was used to index spectral complexity for the phonemes, which were then sorted by sonority status. Results of a between-group comparison with spectral complexity as the independent variable and natural class as the dependent variable revealed the existence of six significantly different groups with spectral complexity ranking according to the sonority hierarchy. These findings suggest that Shannon entropy is a reliable acoustic correlate of sonority and may account for the combinatory patterns of co-occurrence of speech sounds in the speech stream.

Direct classification of all American English phonemes using signals from functional speech motor cortex

Objective. Although brain–computer interfaces (BCIs) can be used in several different ways to restore communication, communicative BCI has not approached the rate or efficiency of natural human speech. Electrocorticography (ECoG) has precise spatiotemporal resolution that enables recording of brain activity distributed over a wide area of cortex, such as during speech production. In this study, we sought to decode elements of speech production using ECoG. Approach. We investigated words that contain the entire set of phonemes in the general American accent using ECoG with four subjects. Using a linear classifier, we evaluated the degree to which individual phonemes within each word could be correctly identified from cortical signal. Main results. We classified phonemes with up to 36% accuracy when classifying all phonemes and up to 63% accuracy for a single phoneme. Further, misclassified phonemes follow articulation organization described in phonology literature, aiding classification of whole words. Precise temporal alignment to phoneme onset was crucial for classification success. Significance. We identified specific spatiotemporal features that aid classification, which could guide future applications. Word identification was equivalent to information transfer rates as high as 3.0 bits s−1 (33.6 words min−1), supporting pursuit of speech articulation for BCI control.

Electrocorticographic correlates of overt articulation of 44 English phonemes: Intracranial recording in children with focal epilepsy

ObjectiveWe determined the temporal–spatial patterns of electrocorticography (ECoG) signal modulation during overt articulation of 44 American English phonemes. MethodsWe studied two children with focal epilepsy who underwent extraoperative ECoG recording. Using animation movies, we delineated ‘when’ and ‘where’ gamma- (70–110Hz) and low-frequency-band activities (10–30Hz) were modulated during self-paced articulation. ResultsRegardless of the classes of phoneme articulated, gamma-augmentation initially involved a common site within the left inferior Rolandic area. Subsequently, gamma-augmentation and/or attenuation involved distinct sites within the left oral-sensorimotor area with a timing variable across phonemes. Finally, gamma-augmentation in a larynx-sensorimotor area took place uniformly at the onset of sound generation, and effectively distinguished voiced and voiceless phonemes. Gamma-attenuation involved the left inferior-frontal and superior-temporal regions simultaneously during articulation. Low-frequency band attenuation involved widespread regions including the frontal, temporal, and parietal regions. ConclusionsOur preliminary results support the notion that articulation of distinct phonemes recruits specific sensorimotor activation and deactivation. Gamma attenuation in the left inferior-frontal and superior-temporal regions may reflect transient functional suppression in these cortical regions during automatic, self-paced vocalization of phonemes containing no semantic or syntactic information. SignificanceFurther studies are warranted to determine if measurement of event-related modulations of gamma-band activity, compared to that of the low-frequency-band, is more useful for decoding the underlying articulatory functions.

Using phase to recognize English phonemes and their distinctive features in the brain

The neural mechanisms used by the human brain to identify phonemes remain unclear. We recorded the EEG signals evoked by repeated presentation of 12 American English phonemes. A support vector machine model correctly recognized a high percentage of the EEG brain wave recordings represented by their phases, which were expressed in discrete Fourier transform coefficients. We show that phases of the oscillations restricted to the frequency range of 2-9 Hz can be used to successfully recognize brain processing of these phonemes. The recognition rates can be further improved using the scalp tangential electric field and the surface Laplacian around the auditory cortical area, which were derived from the original potential signal. The best rate for the eight initial consonants was 66.7%. Moreover, we found a distinctive phase pattern in the brain for each of these consonants. We then used these phase patterns to recognize the consonants, with a correct rate of 48.7%. In addition, in the analysis of the confusion matrices, we found significant similarity-differences were invariant between brain and perceptual representations of phonemes. These latter results supported the importance of phonological distinctive features in the neural representation of phonemes.

Substitution Error Analysis for Improving the Word Accuracy in Telugu Language Automatic Speech Recognition System

Use of natural languages for the computer communication is one of the current research topics. The speech recognition plays a central role in communicating the computer by means of speech. Speech Recognition is the process of converting analog signal into the symbolic gesture form known as text. An Automatic Speech Recognition (ASR) is the process of converting input speech signal given to the system, into text. This input signal is any human spoken word. Though the last Four decades, research is going on bringing the system perception near to the human being, in recognition word accuracy. Many domains play a role in degrading the of system performance in which language and its pronunciation variants caused by different reasons like accent, gender, dialects of the speech are in general factors. In specific, system environment, articulatory phonetics, acoustic phonetics, (acoustic system), lexical model (pronunciation dictionary) and language model including the mood of the speaker. Acoustic modeling can be done in most of the cases by using signal processing, where as lexicon model require a sufficient human intervention as, it is based on the language and human perception. Once sufficient primary data is built then automatic processing can be done using different modeling techniques to derive more data for proper training of the speech recognition system. Here the linguistics are play a major role in building the robust system. In lexical model design language plays a major role. Each language has its own rhythm in speech and language aspects. Based on language rhythm worldly languages are classified as stress timed and syllable timed rhythm. Most of ASR systems use the lexical model that is built for stressed timed languages. All Indian languages are syllable timed rhythmic languages one such is Telugu Language. In this paper analysis of the decoding results of ASR system using two different lexical model environments. One is CMU lexicon which is based on stress timed language as the tool is used American accent English phonemes and another UOH lexicon which is handcraft lexicon for Telugu language which is also a syllable timed language.. Further studied are the gender and accents (pronunciation variant factors) effecting the Substitutional errors in ASR system. The confusion matrix for vowel and consonants alone analyzed for both cases and also for isolated word recognition where the confusion matrix gives the most common phonemes substituted. In all the cases the UOH lexicon based ASR system gives the improvement of word accuracy around 20 to 30%. Speech is a process used to communicate from a speaker to listener. Pronunciation relates to speech, and humans have an intuitive feel for pronunciation. For instance, people chuckle when words are mispronounced and notice when foreign accent colors a speaker's pronunciations.(1). If the words were always pronounced in the same way, ASR would be relatively easy. However, for various reasons words are almost always pronounced differently and varied from one speaker to another and from once situation to another. The variability is due to co-articulation, reasonal accents, speaking rate, speaking style etc.

Classification of intended phoneme production from chronic intracortical microelectrode recordings in speech-motor cortex.

We conducted a neurophysiological study of attempted speech production in a paralyzed human volunteer using chronic microelectrode recordings. The volunteer suffers from locked-in syndrome leaving him in a state of near-total paralysis, though he maintains good cognition and sensation. In this study, we investigated the feasibility of supervised classification techniques for prediction of intended phoneme production in the absence of any overt movements including speech. Such classification or decoding ability has the potential to greatly improve the quality-of-life of many people who are otherwise unable to speak by providing a direct communicative link to the general community. We examined the performance of three classifiers on a multi-class discrimination problem in which the items were 38 American English phonemes including monophthong and diphthong vowels and consonants. The three classifiers differed in performance, but averaged between 16 and 21% overall accuracy (chance-level is 1/38 or 2.6%). Further, the distribution of phonemes classified statistically above chance was non-uniform though 20 of 38 phonemes were classified with statistical significance for all three classifiers. These preliminary results suggest supervised classification techniques are capable of performing large scale multi-class discrimination for attempted speech production and may provide the basis for future communication prostheses.

Environmental design-An expanding role in hearing rehabilitation for older adults

INTRODUCTION The role of the audiologist in aural rehabilitation services on behalf of older adults with hearing impairment is expanding, just as our knowledge of hearing in aging likewise expands [1]. In the past, audiologists generally found that they could not do as much as they desired to assist their older patients in acoustic design modifications to alleviate or prevent environmental interference in communication. This was, in part, probably a result of a lack of academic preparation in the area of environmental design. Training in that area has, in most instances, not been generally available in the majority of preparatory programs. This lack of information has restricted audiology students from learning about an important service that can improve the communicative efficiency of many older adults with impaired hearing function. Rather than letting colleagues continue to rely on a seat of the pants approach to environmental design, this editorial will introduce the concepts and principles of environmental design that take into account aspects of hearing impairment in older adults, including design concepts and the physiological bases for those design considerations. AUDITORY CHANGES IN AGING The complexities involved in the peripheral and central nervous system (CNS) auditory components of presbycusis, along with the compounding effects of the auditory environment, can negatively influence an older adult's ability to communicate in their frequented listening environments. Many public and private listening environments play havoc with aging peripheral and CNS auditory systems. Adults who, at an earlier age, may have noted only some difficulty in specific degraded listening environments may now be experiencing frustrating difficulty. They may blame the difficulties on the speaker, when the problem might be the reverberant characteristics of the meeting room, the anechoic environment of their home, or auditory distractions. These older adults with hearing impairment might begin to avoid places where they would otherwise like to be, increasing their social isolation. Changes in both the peripheral and CNS auditory systems can occur in conjunction with advancing age. The following classic example presents a concise summary of the insidiousness of those changes: Unlike Dr. Oliver Wendell Holmes' New England Deacon who built the wonderful one-horse shay, the architect of the cochlea did not design it to give perfect service for 'a hundred years to a day,' or even for the traditional three-score-and-ten. Its condition in old age, however, seldom represents the effects of aging alone, but rather the accumulative, combined assaults of noise and drugs, as well as [2, p. 139] Many older adults experience a gradual decline in the CNS auditory system's ability to process the acoustic complexities of speech with the speed and accuracy that they possessed in their younger years. If the slightest decline in speed and precision at the level of the brain stem and/or auditory cortex needed to process the acoustic and linguistic components of speech is noted and if that decline in speed of processing is coupled with a peripheral hearing loss in the higher frequency phonemes of speech, which is typical of older adults, then the difficulties that they can experience in hearing and understanding speech will be compounded. Peripheral Auditory System The peripheral auditory system's functioning declines regularly over time. A person's lifestyle, noise exposure, heredity, diet, state of cardiovascular health, and other variables can result in some degree of negative change within the cochlea, with an accompanying sensorineural hearing loss--a gradually progressive sensorineural hearing loss that typically involves the higher frequencies. Since approximately two-thirds of American English phonemes possess important high-frequency acoustic components, a hearing loss that primarily involves a decline in the higher frequencies can negatively affect speech understanding. …

A speech audiogram of Setswana consonants

Setswana is a Bantu language used in several regions of Southern Africa, and its phonemic inventory includes a diverse range of consonants. To date, very little information exists about the acoustic correlates of Setswana speech sounds. The present study was aimed at analyzing these speech sounds in order to develop a clinically useful speech audiogram for Setswana. Three native speakers of Setswana produced 45 target phonemes in word initial and medial positions, in three vowel contexts (/a/, /i/, and /u/). The stimuli were then analyzed for peak frequency and intensity. A preliminary analysis revealed an effect of word position and vowel context on peak frequency, and hence, only phonemes in the word medial position and in the /a/ vowel context were used to plot the speech audiogram. The speech audiogram hence developed was then compared to speech audiograms of American English phonemes commonly employed in clinical settings. Consonants common to both Setswana and American English inventories were used to establish the validity of the study’s procedures. The speech audiogram developed can potentially be used to provide partial estimates of the audibility of Setswana phonemes to native speakers with various types of hearing loss. a)Currently at the Dept. of Communication Pathology, Univ. of Pretoria, South Africa

Listener variability and multiple perception processes

The relationship between the perception of individual phonemes and the perception of words is investigated to determine if these are similar tasks for listeners. Since listeners may be able to use top-down processes in full words, it is argued that, at least for some, the task of identifying isolated phonemes may be very different from the task of identifying a full word. Because greater variability in performance is expected from non-native speakers, 15 native speakers of Sudanese Arabic (as well as a control group of 12 native speakers of American English) were tested on identification of American English phonemes in word context and the same instance of these phonemes extracted from the words. The overall agreement between corresponding items on the two tests was significantly better than chance, but scores of individual subjects varied substantially, with phoneme-word test agreement falling below chance for many subjects. Additionally, not all non-native subjects performed better on the full word task, suggesting that they do not all use higher-level information. It is therefore argued that studies of phoneme-level perception are more relevant to some listeners’ word perception than to others’.

Repetition and Recognition of Nonsense

A most important feature of the perceptual capacities contributing to the effective reception of linguistic events is that, even when the events are without lexical status for the listener, he can nonetheless assign a nonlexical, that is to say, phonemic identity to them. In order to examine the process of phonemic identification, particularly in the light of the articulatory reference conceptualization of this process posited by the Haskins group, CCVC syllables were developed that, although composed of only general American English phonemes, did not conform to the restrictions on English syllable formation. Carrier phrases were also developed for each syllable within which it was compliant with these restrictions, so that, for example, the carrier for /ŋziž/ was /ɡʌŋziz_ɔŋ/. Recordings of the syllables, both in and out of carriers, were presented to listeners for repetition. In addition, a recognition test was conducted in which the listeners were required to decide which, among systematic phonemic departures from them, were the events that they had previously repeated. The contingencies between repetition and recognition performances for the two sets of events are discussed.

On “American English Phonemes”

First Page

American English Phonemes

In order to be useful as a basis for frequency tables for American English phonemes, retranscriptions of existing word lists must take account of recent advances in phonemic theory as applied to the study of American English structure, and must be based on freshly recorded utterances representing a significant number of important dialect varieties. Routine assignment of the traditional IPA symbols is inadequate.