Acoustic characteristics of American English vowels

Hillenbrand, James; Getty, Laura A.; Wheeler, Kimberlee; Clark, Michael J.

doi:10.1121/1.409456

Cited by 552 publications

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“…These cues have been shown to be sufficient for normal hearing listeners to achieve high levels of vowel recognition when listening to monophthongal vowels (Peterson and Barney, 1952;Chistovich and Lublinskaya, 1979;and Hillenbrand et al 1995). Therefore, out of the 12 vowels used by Fu et al (2002), only the vowel identification data that included the nine nominally monophthongal vowels (in /h/-vowel-/d/ context) were used in the present study : 'had', 'hawed', 'head', 'heed', 'hid', 'hod', 'hood', 'hud', and 'who'd'. That is, the diphthongs 'hayed' and 'hoed' were excluded because they are characterized by time-varying formant cues, and the r-colored vowel 'heard' was excluded because it is characterized by a low third formant.…”

Section: Methodsmentioning

confidence: 99%

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A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant Users

Sagi

Galvin

et al. 2009

JARO

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In the present study, a computational model of phoneme identification was applied to data from a previous study, wherein cochlear implant (CI) users' adaption to a severely shifted frequency allocation map was assessed regularly over 3 months of continual use. This map provided more input filters below 1 kHz, but at the expense of introducing a downwards frequency shift of up to one octave in relation to the CI subjects' clinical maps. At the end of the 3-month study period, it was unclear whether subjects' asymptotic speech recognition performance represented a complete or partial adaptation. To clarify the matter, the computational model was applied to the CI subjects' vowel identification data in order to estimate the degree of adaptation, and to predict performance levels with complete adaptation to the frequency shift. Two model parameters were used to quantify this adaptation; one representing the listener's ability to shift their internal representation of how vowels should sound, and the other representing the listener's uncertainty in consistently recalling these representations. Two of the three CI users could shift their internal representations towards the new stimulation pattern within 1 week, whereas one could not do so completely even after 3 months. Subjects' uncertainty for recalling these representations increased substantially with the frequency-shifted map. Although this uncertainty decreased after 3 months, it remained much larger than subjects' uncertainty with their clinically assigned maps. This result suggests that subjects could not completely remap their phoneme labels, stored in long-term memory, towards the frequency-shifted vowels. The model also predicted that even with complete adaptation, the frequency-shifted map would not have resulted in improved speech understanding. Hence, the model presented here can be used to assess adaptation, and the anticipated gains in speech perception expected from changing a given CI device parameter.

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Section: Methodsmentioning

confidence: 99%

“…natural productions recorded from five men, five women, and five children (one production each), and were drawn from the larger corpus of speech samples collected by Hillenbrand et al (1995).…”

Section: Methodsmentioning

confidence: 99%

A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant Users

Sagi

Galvin

et al. 2009

JARO

View full text Add to dashboard Cite

show abstract

“…Vowel and consonant syllable identification tests were administered. The vowel syllable identification test used 12 vowels presented in a /h/-vowel-/d/ context (had, hayed, hawed, head, heard, heed, hid, hod, hoad, hood, hud, who'd) (Hillenbrand et al 1995). Two male (talkers 48 and 49) and two female (talkers 39 and 44) talkers were used of the multiple talkers available in these test materials.…”

Section: Methodsmentioning

confidence: 99%

Effects of Stimulus Level on Speech Perception with Cochlear Prostheses

Franck

Pfingst

2003

JARO - Journal of the Association for Research in Otolaryngolog

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This study is one of a series that examines stimulus features important for cochlear implant function. Here, we examine effects of stimulus level. In subjects with cochlear implants, a number of psychophysical tests of temporal discrimination (pulse rate discrimination, gap detection, etc.) show marked improvement as a function of stimulus level through most or all of the dynamic range, while electrode-place discrimination can improve or degrade as a function of level. In this study, effects of these combined potential influences were studied by examining the effects of stimulus level on syllable identification. We tested two hypotheses: that syllable identification varies as a function of stimulus level and that level and electrode configuration interact in affecting syllable identification. We examined vowel and consonant identification as a function of stimulus level for bipolar and monopolar electrode configurations. We used experimental processor maps where upper and lower stimulation limits of each electrode pair were equated to eliminate confounding effects of dynamic range, which varies across subjects and electrodes. For each channel, stimulation amplitude was set to a fixed percentage of its dynamic range. Eight adult subjects with Nucleus CI24M implants were tested using the SPEAK processing strategy. With each electrode configuration, stimulus levels were tested from 0% to 90% of the dynamic range in nine steps. The effects on consonant and vowel identification were similar. Phoneme identification was usually better for monopolar than for bipolar stimulation. In the lower half of the dynamic range, syllable identification usually increased as a function of stimulus level. In the upper half of the dynamic range, syllable identification continued to increase as a function of level to 90% of the dynamic range for some subjects, while for others there was no appreciable change or a decrease as a function of level. Decreases in performance at high levels were more common with monopolar than bipolar stimulation. These results suggest that if speech processors are programmed to optimize level for each individual, speech perception performance could be improved.

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“…The vowel set included 10 monophthongs (/i I ( ae u H a 0 c `Ą /) and two diphthongs (/o e/), presented in a /h/-vowel-/d/ context. The tokens for vowel recognition test were digitized natural productions from five men and five women drawn from speech samples collected by Hillenbrand et al (1995). Consonant recognition was measured in a 20-alternative identification paradigm.…”

Section: Test and Training Materialsmentioning

confidence: 99%

Auditory Training with Spectrally Shifted Speech: Implications for Cochlear Implant Patient Auditory Rehabilitation

Nogaki

Galvin

2005

JARO

113

122

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After implantation, postlingually deafened cochlear implant (CI) patients must adapt to both spectrally reduced and spectrally shifted speech, due to the limited number of electrodes and the limited length of the electrode array. This adaptation generally occurs during the first three to six months of implant use and may continue for many years. To see whether moderate speech training can accelerate this learning process, 16 naïve, normal-hearing listeners were trained with spectrally shifted speech via an eightchannel acoustic simulation of CI speech processing. Baseline vowel and consonant recognition was measured for both spectrally shifted and unshifted speech. Short daily training sessions were conducted over five consecutive days, using four different protocols. For the test-only protocol, no improvement was seen over the five-day period. Similarly, sentence training provided little benefit for vowel recognition. However, after five days of targeted phoneme training, subjects' recognition of spectrally shifted vowels significantly improved in most subjects. This improvement did not generalize to the spectrally unshifted vowel and consonant tokens, suggesting that subjects adapted to the specific spectral shift, rather than to the eightchannel processing ingeneral. Interestingly, significant improvement was also observed for the recognition of spectrally shifted consonants. The largest improvement was observed with targeted vowel contrast training, which did not include any explicit consonant training. These results suggest that targeted phoneme training can accelerate adaptation to spectrally shifted speech. Given these results with normalhearing listeners, auditory rehabilitation tools that provide targeted phoneme training may be effective in improving the speech recognition performance of adult CI users.

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Acoustic characteristics of American English vowels

Cited by 552 publications

References 0 publications

A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant Users

A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant Users

Effects of Stimulus Level on Speech Perception with Cochlear Prostheses

Auditory Training with Spectrally Shifted Speech: Implications for Cochlear Implant Patient Auditory Rehabilitation

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