Objective evaluation of nasality using laser Doppler vibrometer
Masanobu KumadaToshiaki KanekoTakahiko OnoMasanao OhashiKōji IshidaKazuo NakayamaNoriko KobayashiHajime HiroseNiro TayamaSeiji Niimi
0
Citation
0
Reference
10
Related Paper
Abstract:
Objective measurement of nasality is very important in terms of clinical evaluation. But there is no definite methodology of objective evaluation of nasality. We already reported that new methodologies of the Laser Doppler Vibrometer (LDV) and Sub-miniature Electret Microphone (SEM), both of which could detect the nasal/non-nasal difference of sustained phonemes, seemed valid to evaluate nasality [Kumada et al., 140th ASA Meeting (2000); Kumada et al., 141st ASA Meeting (2001)]. LDV, used recently in an industrial field as well as medical/biological field, is the generator and the detector of the laser to detect the velocity of the object’s vibration by Doppler’s effect. LDV seemed a powerful tool for speech physiology by which vibration of a body wall can be measured during speech and singing, without any contact receiver. The objectives were to evaluate the degree of nasality of phonemes in words by LDV and SEM, and to discuss the possibility of the clinical use of these methodologies. The subjects were 5 healthy Japanese males (Tokyo dialect speakers). The materials were Japanese words /shinkansen/ and /shimbunshi/. Both LDV and SEM systems could detect a nasal/non-nasal difference in spoken words, and seemed valid to evaluate nasality in speech. Further study is planned using patients (e.g., cleft-palate) as well as healthy subjects.Keywords:
Nasality
Nasalization
In this paper a description is given of four of the primary acoustic features that have been found to be associated with the nasalization of vowels. Comparative normal-nasal spectra are portrayed for several vowels, and explanations to account for each of the prominent within-vowel differences are offered. In addition, other evidence is presented which is used to suggest that each of the primary acoustic features of nasalization may also be the result of factors quite unrelated to nasal coupling. These factors, manifestations of typical normal variations, are used to develop the thesis that it is not readily possible to isolate the acoustic features of nasalization within a given vowel spectrum. The implications of this thesis are then manifest in a questioning of the validity of the term, nasality.
Nasalization
Nasality
Nasal vowel
Cite
Citations (7)
This study was supported by the National Research Foundation of Korean Grant funded by the Korean Government (NRF2013S1A2A2035410) to Taehong Cho.
Nasalization
Nasality
Nasal vowel
Cite
Citations (2)
Objectives: To examine the amplitude-temporal relationships of acoustic nasalization in speakers with a range of nasality and to determine the extent to which each domain independently predicts the speaker’s perceived oral-nasal balance. Design: Rate-controlled speech samples, consisting of /izinizi/, /azanaza/, and /uzunuzu/, were recorded from 18 participants (14 with repaired cleft palate and 4 without cleft palate) using the Nasometer. The mean nasalance of the entire mid-vowel–nasal consonant–vowel (mid-VNV) sequence (amplitude-domain) and the duration of the nasalized segment of the mid-VNV sequence (temporal-domain) were obtained based on nasalance contours. Results: Strong linear and vowel-dependent relationships were observed between the 2 domains of nasalization (adjusted R 2 = 71.5%). Both the amplitude- and temporal-domain measures were found to reliably predict the speaker’s perceived oral-nasal balance, with better overall model fit and higher classification accuracy rates observed in /izinizi/ and /uzunuzu/ than in /azanaza/. Despite poor specificity, the temporal-domain measure of /azanaza/ was found to have a strong correlation with the participants’ Zoo passage nasalance scores ( r s = .897, p < .01), suggesting its potential utility as a severity indicator of perceived nasality. Conclusions: With the use of relatively simple speech tasks and measurements representing the amplitude and temporal domains of nasalization, the present study provided practical guidelines for using the Nasometer in assessing patients with oral-nasal resonance imbalance. Findings suggest that both domain measures of nasalization should be examined across different vowel contexts, given that each domain may provide clinically relevant, yet different, information.
Nasalization
Nasality
Nasal vowel
Cite
Citations (5)
The assumption of minimal articulatory difference between members of nasal–oral vowel pairs deserves greater scrutiny. This study tests the hypothesis that members of nasal–oral vowel pairs share a common vocal tract configuration. Electromagnetic articulography is used to study the vertical position of the tongue and the labial aperture of nasal–oral vowel pairs produced by four speakers of Brazilian Portuguese. Significant differences were found for each vowel pair for at least one speaker, though considerable inter-speaker variation was evident. The most robust differences were tongue-body raising during the nasal vowels /ã/ and /ũ/. Because heavy nasalization tends to raise the perceived quality of low vowels, the lingual raising of /ã/ probably reinforces its nasality and contributes to the description of this vowel as [ɐ]. Because nasalization tends to lower the perceived quality of high vowels, the nasality of /ũ/ may be counteracted by the lingual raising gesture.
Nasal vowel
Cite
Citations (6)
The effects of feedback filtering on nasality perception were investigated by having speakers produce sentences while hearing their voices unfiltered and low-pass filtered with cut-off frequencies of 1000, 500, and 300 Hz. As they spoke, speakers judged the nasality in their productions using a ratio scale. Measurements of nasalization were made with a miniature accelerometer attached to the side of the speaker's nose. Data obtained indicate that the speakers decreased their nasalization slightly when they heard their voices low-pass filtered at each cut-off frequency. However, they did not perceive consistent changes in their own nasality during the filtered conditions. These findings are interpreted as suggesting that nasalization is influenced by filtering air-conducted auditory information and that relationships between the acoustic correlates of nasalization and self-perception of nasality are complex.
Nasalization
Nasality
QUIET
Cite
Citations (5)
The phonetic realization of nasal vowels produced by Pwo speakers of different ages can vary. The present study investigated mid and low nasal vowels of Pwo speakers from Mae Hong Son province, Thailand. Due to the higher tendency of language contact with Thai, the younger group’s nasal vowels were expected to lose more nasality than the older group. The emergence of final nasal consonants was also expected in the younger group. The nasalization duration and consonant duration of both groups were analyzed. The results showed that, regardless of age, mid nasal vowels of some speakers had final nasal consonants, while low nasal vowels of all speakers did not. Furthermore, the older group had both longer nasalization duration and consonant duration than the younger group, suggesting their higher tendency to preserve nasality. The younger group had shorter nasalization duration and consonant duration, indicating the loss of nasality in vowels without compensatory final nasal consonants. The change might be due to the vowel quality. High vowels were fully denasalized with no compensatory final nasal consonants. Mid vowels were nasalized with the emergence of final nasal consonants. Low vowels remained nasalized without final nasal consonants. We could not confirm that the emergence of final nasal consonants was induced by Thai because it occurred in both groups. The existence of final nasal consonants in the younger group could not be used as evidence of an effect of contact.
Nasality
Nasalization
Nasal vowel
Cite
Citations (0)
In this paper acoustics and synthesis of nasalization is studied based on a comprehensive computer model of the vocal tract: TRACTTALK. TRACTTALK simulates the vocal-tract system in the frequency domain and derives the time-domain equivalent to produce sound output. It incorporates all important components of the system and decomposes the transfer function into its zero and pole parts. Such a decomposition enables one to accurately estimate poles and zeros of a nasalized sound. First, temporal trajectories of poles/zeros are examined as a function of the velopharyngeal opening, the presence of the nasal sinuses, and other articulatory parameters. This is in follow-up to previous work [Flanagan, AT&T Bell Labs. internal report (1983)]. The attempt is to systematically characterize the pole/zero pattern of nasalization for improving the performance of formant tracking and feature labeling algorithms. Secondly, synthesis of nasalization is described using TRACTTALK. Listening experiments are conducted to assess the relationships among perceived nasality, inclusion of the nasal sinuses, and the degree of the velopharyngeal opening. It is found, e.g., that inclusion of the nasal sinuses results in stronger perceived nasality. While the literature reports differing views on the role of sinuses in nasality, these results are consistent with the findings of Maeda [Proc. ICASSP 2, 911–914 (1982)]. Synthetic speech generated from the vocal-tract system will be demonstrated.
Nasalization
Nasality
Vocal tract
Nasal vowel
Cite
Citations (1)
Coarticulatory patterns in nasality in two West African languages—Akan and Efik—will be described. These languages make different phonological use of the feature (nasal). Nasality is determined from nasal and oral airflow as recorded with a Rothenburg split mask. The focus is on the timing of contextual nasalization; in particular, the coarticulatory effects of nasal consonants on adjacent vowels that are not contrastively (+ nasal). These effects are said to vary depending on the phonological use of nasality in a language. In Akan, there is an oral/nasal contrast on vowels, even in the environment of nasal consonants; thus contextual nasalization may be limited, so as to preserve the phonemic contrast. In Efik, there is no such contrast on vowels, so contextual nasalization of vowels may be more extensive, beginning earlier, and ending later, as has been reported elsewhere for English. Data for several speakers of each language will be discussed. [Work supported by NSF.]
Nasalization
Nasality
Nasal vowel
Cite
Citations (10)
Phonological studies reveal an apparent paradox. On the one hand, distinctive vowel nasalization often develops diachronically from loss of a contiguous, especially a following, nasal consonant. On the other hand, synchronic distinctive nasalization rarely occurs on vowels before nasal consonants. This paradox could be resolved if it could be shown that non-distinctive assimilatory vowel nasalization becomes perceptually more evident as the nasal consonant (the segment conditioning the nasalization) weakens and becomes less evident. To test this hypothesis, natural-speech tokens of /mIm/, /mUm/, and /mam/ were digitally processed so that the m's were either unaltered, reduced in amplitude to −12, −24, or −36 dB (with respect to their original amplitude), or eliminated completely. Eleven subjects made scalar judgements of the perceived degree of nasality of the vowel in each stimulus, and seven subjects determined the relative nasality of paired stimuli. The results indicate that although the mere presence of a contiguous nasal consonant endows a vowel with some apparent nasality, the gradual reduction of the nasal consonant, as hypothesized, enhances their perceived nasality. [Supported by NSF.]
Nasality
Nasalization
Nasal vowel
Stimulus (psychology)
Cite
Citations (1)
The phonetic realization of nasal vowels produced by Pwo speakers of different ages can vary. The present study investigated mid and low nasal vowels of Pwo speakers from Mae Hong Son province, Thailand. Due to the higher tendency of language contact with Thai, the younger group’s nasal vowels were expected to lose more nasality than the older group. The emergence of final nasal consonants was also expected in the younger group. The nasalization duration and consonant duration of both groups were analyzed. The results showed that, regardless of age, mid nasal vowels of some speakers had final nasal consonants, while low nasal vowels of all speakers did not. Furthermore, the older group had both longer nasalization duration and consonant duration than the younger group, suggesting their higher tendency to preserve nasality. The younger group had shorter nasalization duration and consonant duration, indicating the loss of nasality in vowels without compensatory final nasal consonants. The change might be due to the vowel quality. High vowels were fully denasalized with no compensatory final nasal consonants. Mid vowels were nasalized with the emergence of final nasal consonants. Low vowels remained nasalized without final nasal consonants. We could not confirm that the emergence of final nasal consonants was induced by Thai because it occurred in both groups. The existence of final nasal consonants in the younger group could not be used as evidence of an effect of contact.
Nasality
Nasalization
Nasal vowel
Cite
Citations (0)