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T L Gottfried

Publications and source records attributed to T L Gottfried.

6 recordsLinked to original sources
PubMed1990

Effect of speaking rate on the perception of vowels.

Three experiments examined the conditions under which the speaking rate of a context sentence affects vowel identification. In these experiments, listeners identified the vowel in synthetic /b/-vowel-/t/ syllables that varied systematically in the duration (temporal), the formant frequencies (spectral), or both the duration and formant frequencies (temporal-spectral) of the steady-state portion of the syllable. These syllables were embedded in two synthetic sentence frames, one with the temporal characteristics of a natural fast sentence and one with those of a slow sentence. For two vowel distinctions that are specified in natural speech by both temporal and spectral characteristics, /I/-/i/ and /e/-/ae/, listeners adjusted their identification of the vowels according to the sentence rate in all three conditions. Although there was a trend for the rate effect to be reduced in the temporal-spectral condition, the influence of sentential rate was never eliminated. By contrast, for a vowel distinction that is naturally specified primarily by spectral characteristics, /e/-/I/, there was no effect of sentence rate in any of the conditions. We conclude that when vowels are differentiated in natural speech by both temporal and spectral information, listeners obligatorily use the duration of the vowel to identify it and do so in relation to the rate of the sentence in which the vowel occurs.

Adult↗
PubMed1988

Trading relations in the perception of /r/-/l/ by Japanese learners of English.

The role of language-specific factors in phonetically based trading relations was examined by assessing the ability of 20 native Japanese speakers to identify and discriminate stimuli of two synthetic /r/-/l/ series that varied temporal and spectral parameters independently. Results of forced-choice identification and oddity discrimination tasks showed that the nine Japanese subjects who were able to identify /r/ and /l/ reliably demonstrated a trading relation similar to that of Americans. Discrimination results reflected the perceptual equivalence of temporal and spectral parameters. Discrimination by the 11 Japanese subjects who were unable to identify the /r/-/l/ series differed significantly from the skilled Japanese subjects and native English speakers. However, their performance could not be predicted on the basis of acoustic dissimilarity alone. These results provide evidence that the trading relation between temporal and spectral cues for the /r/-/l/ contrast is not solely attributable to general auditory or language-universal phonetic processing constraints, but rather is also a function of phonemic processes that can be modified in the course of learning a second language.

Adolescent↗
PubMed1986

Intelligibility of vowels sung by a countertenor.

Ten American English vowels were sung in a /b/-vowel-/d/ consonantal context by a professional countertenor in full voice (at F0 = 130, 165, 220, 260, and 330 Hz) and in head voice (at F0 = 220, 260, 330, 440, and 520 Hz). Four identification tests were prepared using the entire syllable or the center 200-ms portion of either the full-voice tokens or the head-voice tokens. Listeners attempted to identify each vowel by circling the appropriate word on their answer sheets. Errors were more frequent when the vowels were sung at higher F0. In addition, removal of the consonantal context markedly increased identification errors for both the head-voice and full-voice conditions. Back vowels were misidentified significantly more often than front vowels. For equal F0 values, listeners were significantly more accurate in identifying the head-voice stimuli. Acoustical analysis suggests that the difference of intelligibility between head and full voice may have been due to the head voice having more energy in the first harmonic than the full voice.

Humans↗
PubMed1980

Task variables in the study of vowel perception.

Vowels produced in isolation by six speakers were identified less accurately than vowels coarticulated in /k/-vowel-/k/ syllables, whether tested by a key word task or by a rhyming task. Performance by naive listeners in the two tasks was highly correlated.

Humans↗
PubMed1980

Identification of coarticulated vowels.

Previous explanations of vowel perception held that the most definitive information for vowel identity is the relatively constant formant frequencies in the steady-state portions of vowels. Perceptual studies indicate, however, that vowels spoken in syllables with labial stop consonants are identified more accurately than vowels spoken in isolation. The present study investigated the nature and scope of this consonantal context advantage in the perception of ten American English vowels spoken by adult male and female speakers. Vowels in /p/-vowel-/p/, /b/-vowel-/b/, /k/-vowel-/k/, /k/, /k/-vowel, and vowel-/k/ syllables were identified much more accurately than isolated vowels. This is consistent with the hypothesis that dynamic acoustic information due to the coarticulation in syllables is important for vowel identification. Identification of vowels in /g/-vowel-/g/, /g/-vowel, and vowel-/g/ syllables was not better than isolated vowels and was significantly poorer than for other consonantal contexts. Acoustical analyses were performed to determine whether poor production of vowels could account for perceptual errors. Misproduced vowel targets could not account for the overall pattern of identification performance. Phonological factors were also considered but were found to be inadequate to account fully for the results.

Adult↗