Talker Familiarity Research Articles

The Contributions of Talker Familiarity and Individual Talker Characteristics

The article details a two‐phase study investigating the relative contributions of talker‐familiarity and talker‐intelligibility to L2 listening comprehension by learners in a classroom setting. Students from beginning to low‐intermediate German FL classes participated in German language listening tasks, being exposed to speech by their German teacher (familiar talker) and other, unfamiliar talkers. Findings were consistent in both phases of the study: the relative intelligibility of particular talkers was more predictive to L2 listening accuracy than familiarity with the talker. Follow‐up investigations revealed a relationship between speech rate and listening comprehension accuracy.

A cross-language familiar talker advantage

Previous research has shown that familiar talkers are more intelligible than unfamiliar talkers. In the current study, we tested the source of this familiar talker advantage by manipulating the type of talker information available to listeners. Two groups of native English listeners were familiarized with the voices of five German-English bilingual talkers; one group learned the voices from German stimuli and the other from English stimuli. Thus, English-trained listeners had access to both language-independent and English-specific talker information, while German-trained listeners had access to language-independent and German-specific talker information. After three days of voice learning, all listeners performed a word recognition task in English. Consistent with previous findings, English-trained listeners found the speech of familiar talkers to be more intelligible than unfamiliar talkers, as measured by whole words and phonemes correct. In contrast, German-trained listeners showed no familiar talker advantage, suggesting that listeners must have knowledge of talker-specific, linguistically relevant information to elicit the familiar talker advantage and that knowledge of language-independent talker information - such as size and shape of the vocal tract - does not facilitate speech perception.

Amodal specification of talker-specific motor behavior

There is substantial evidence that the speech perception function incorporates information for articulatory motor behavior. Research over the last 15 years has shown that speech perception also uses information for talker-specific motor behavior. Interestingly, this research reveals that talker information can facilitate speech perception whether it is apprehended through auditory or visual speech (lipread) means. The multimodal nature of these effects could mean that the talker-specific properties used by the system are amodal and motoric-or gestural-in nature. Evidence for this proposition-that talker-specific facilitation of speech is based on amodal specification of gestural style-will be discussed. This evidence includes findings that isolated talker-specific phonetic information, available both optically and acoustically, can be informative about talker identity to the degree that it supports cross-modal talker matching. Other evidence shows that the talker familiarity gained through one modality can facilitate perception of speech in the other. Finally, recent evidence reveals that speech perceivers will align to (inadvertently imitate) talker-specific properties of utterances they are asked to shadow, whether that speech is presented auditorily or visually. These results suggest that some of the 'motor knowledge' bearing on speech perception takes the form of talker-specific gestural properties, amodally specified.

Talker‐specific and accent‐general perceptual adaptation to Korean‐accented English

The present study investigated the relative contribution of talker‐specific and accent‐general learning to the perceptual adaptation of accented speech. Adult native English‐speaking listeners were asked to transcribe Korean‐accented English words in a brief, high variability perceptual learning paradigm. During training, listeners transcribed individual words produced by six Korean‐accented speakers and were given feedback on their transcription performance. Controls were either trained with native English speakers or were given no training. At test, listeners were presented with Korean‐accented speech produced by both familiar and unfamiliar talkers. The results suggest that listeners learned accent‐general properties of nonnative speech. Listeners showed better transcription performance for both familiar and unfamiliar accented talkers relative to English and no training controls. However, talker‐specific properties such as individual talker familiarity and baseline intelligibility also influenced transcription performance at test. These findings suggest that although listeners are sensitive to multiple sources of variation in speech, they appear to engage in accent‐general perceptual adaptation to non‐native speech.

Lipread me now, hear me better later: Crossmodal transfer of talker familiarity effects

There is evidence that for both auditory and visual speech perception (lipreading) familiarity with a talker facilitates speech recognition [Nygaard et al., Psychol. Sci. 5, 42 (1994); Yakel et al., Percept. Psychophys. 62, 1405 (2000)]. Explanations of these effects have concentrated on the retention of talker information specific to each of these modalities. It could be, however, that some amodal, talker-specific articulatory style information is retained to facilitate speech perception in both modalities. If this is true, then experience with a talker in one modality should facilitate perception of speech from that talker in the other modality. To test this prediction, subjects were given one hour of experience lipreading from a talker and were then asked to recover speech-in-noise from either this same talker or from a different talker. Results revealed that subjects who lipread and heard speech from the same talker performed better on the speech-in-noise task than did subjects who lipread from one talker and then heard speech from a different talker.

The effect of talker familiarity on stream segregation

This study contrasts different forms of familiarity with a talker's voice, to better explore how these types of familiarity might influence a listener's ability to understand that voice in the context of noise. Listeners were asked to shadow a target voice while a second voice spoke fluently in the background. Listeners differed in their familiarity with the target voice: one group was familiar with the voice and were told explicitly whose voice they would be hearing (explicit knowledge); a second group was familiar with the target voice but were not warned whose voice it was (implicit knowledge), and members of a third group were entirely unfamiliar with the target voice. Explicit knowledge of talker identity appeared to have the larger effect on listener performance: Participants with explicit knowledge made significantly fewer shadowing errors than those with only implicit familiarity. Familiarity did influence the types of errors listeners made: those participants who were familiar with the target voice prior to the test session made fewer incorrect responses than did those who had not heard the talker previously, although their total number of errors (including misses, as well as incorrect responses) did not differ. In a second experiment, neither explicit knowledge of a distracter voice's identity nor implicit familiarity with the background speaker had any effect on shadowing a target voice. This suggests that familiarity with a voice only helps listeners when that voice is the one being attended. These studies suggest that there may be more than one manner in which talker-specific information influences perception.

Effect of Training on Word-Recognition Performance in Noise for Young Normal-Hearing and Older Hearing-Impaired Listeners

The objective of this study was to evaluate the effectiveness of a training program for hearing-impaired listeners to improve their speech-recognition performance within a background noise when listening to amplified speech. Both noise-masked young normal-hearing listeners, used to model the performance of elderly hearing-impaired listeners, and a group of elderly hearing-impaired listeners participated in the study. Of particular interest was whether training on an isolated word list presented by a standardized talker can generalize to everyday speech communication across novel talkers. Word-recognition performance was measured for both young normal-hearing (n = 16) and older hearing-impaired (n = 7) adults. Listeners were trained on a set of 75 monosyllabic words spoken by a single female talker over a 9- to 14-day period. Performance for the familiar (trained) talker was measured before and after training in both open-set and closed-set response conditions. Performance on the trained words of the familiar talker were then compared with those same words spoken by three novel talkers and to performance on a second set of untrained words presented by both the familiar and unfamiliar talkers. The hearing-impaired listeners returned 6 mo after their initial training to examine retention of the trained words as well as their ability to transfer any knowledge gained from word training to sentences containing both trained and untrained words. Both young normal-hearing and older hearing-impaired listeners performed significantly better on the word list in which they were trained versus a second untrained list presented by the same talker. Improvements on the untrained words were small but significant, indicating some generalization to novel words. The large increase in performance on the trained words, however, was maintained across novel talkers, pointing to the listener's greater focus on lexical memorization of the words rather than a focus on talker-specific acoustic characteristics. On return in 6 mo, listeners performed significantly better on the trained words relative to their initial baseline performance. Although the listeners performed significantly better on trained versus untrained words in isolation, once the trained words were embedded in sentences, no improvement in recognition over untrained words within the same sentences was shown. Older hearing-impaired listeners were able to significantly improve their word-recognition abilities through training with one talker and to the same degree as young normal-hearing listeners. The improved performance was maintained across talkers and across time. This might imply that training a listener using a standardized list and talker may still provide benefit when these same words are presented by novel talkers outside the clinic. However, training on isolated words was not sufficient to transfer to fluent speech for the specific sentence materials used within this study. Further investigation is needed regarding approaches to improve a hearing aid user's speech understanding in everyday communication situations.

Infant’s perception of speech in noise: Effect of the number of background talkers

A number of recent studies have investigated infants’ abilities to hear speech in noise [Newman & Jusczyk, ‘‘The cocktail party effect in infants,’’ Percep. Psychophs. 58, 1145–1156 (1996); Newman, R. S., ‘‘The cocktail party effect in infants revisited: Listening to one’s name in noise,’’ Develop. Psychol. 41, 352–362 (2005); Barker & Newman, ‘‘Listen to your mother! The role of talker familiarity in infant streaming,’’ Cognition, 94, B45–B53 (2004); Hollich, et al., ‘‘Infants’ use of synchronized visual information to seperate streams of speech,’’ Child Develop. 76, 598–613 (2005)]. In the current study, we examine how the type of background noise influences infants’ ability to understand speech. Infants aged 5 months heard a talker repeat either their own name or another infant’s name in the presence of one of 3 types of background noise: multitalker babble, a single background talker, or a single talker reversed in time. With multitalker babble, infants could recognize their name (shown by longer listening to own-name than other-name test trials) only when the target speech was at least 10 dB more intense than the background. However, even at this high SNR, infants fail to recognize their name when the background consists of a single talker. This difficulty is not the result of semantic information or speechlike properties from the single talker; infants likewise fail when the single talker is temporally reversed. Rather, infants appear to be distracted by signals containing the time-varying amplitude patterns of a human voice, and do not appear to benefit from the dips in noise amplitude that occur with a single voice.

Listen to your mother! The role of talker familiarity in infant streaming

Little is known about the acoustic cues infants might use to selectively attend to one talker in the presence of background noise. This study examined the role of talker familiarity as a possible cue. Infants either heard their own mothers (maternal-voice condition) or a different infant's mother (novel-voice condition) repeating isolated words while a female distracter voice spoke fluently in the background. Subsequently, infants heard passages produced by the target voice containing either the familiarized, target words or novel words. Infants in the maternal-voice condition listened significantly longer to the passages containing familiar words; infants in the novel-voice condition showed no preference. These results suggest that infants are able to separate the simultaneous speech of two women when one of the voices is highly familiar to them. However, infants seem to find separating the simultaneous speech of two unfamiliar women extremely difficult.

Effects of Talker Variability on Perceptual Learning of Dialects

Two groups of listeners learned to categorize a set of unfamiliar talkers by dialect region using sentences selected from the TIMIT speech corpus. One group learned to categorize a single talker from each of six American English dialect regions. A second group learned to categorize three talkers from each dialect region. Following training, both groups were asked to categorize new talkers using the same categorization task. While the single-talker group was more accurate during initial training and test phases when familiar talkers produced the sentences, the three-talker group performed better on the generalization task with unfamiliar talkers. This cross-over effect in dialect categorization suggests that while talker variation during initial perceptual learning leads to more difficult learning of specific exemplars, exposure to intertalker variability facilitates robust perceptual learning and promotes better categorization performance of unfamiliar talkers. The results suggest that listeners encode and use acoustic-phonetic variability in speech to reliably perceive the dialect of unfamiliar talkers.

Visual contributions to talker attunement

Listeners can attune to talker-specific speech patterns, as demonstrated by findings of greater accuracy in spoken-words-in-noise identification for words spoken by familiar voices [e.g., Nygaard and Pisoni, Percept. Psychophys. 60, 355–376 (1998)]. In previous demonstrations of this effect, talker familiarity was produced by auditory speech exposure. The purpose of the present study was to examine the contribution of visible speech information to talker attunement. First, the auditory attunement effect was replicated: Participants were given extensive exposure to auditory words spoken by different talkers, and were subsequently tested on novel words in noise spoken by one of the familiar talkers and by a talker not previously heard. Identification of the words was more accurate for the familiar talker. This procedure was then extended to include video presentations of the talker’s articulating face along with each word during the exposure phase. To control for familiarity with the faces, a separate condition included presentation of static images of the talkers’ faces. Visual articulations were not presented during the identification-in-noise task. Thus, the experiment tests whether visual exposure to talker’s articulatory patterns contributes to talker attunement, and, specifically, whether any such visual contributions to talker attunement generalize to auditory speech perception. [Work supported by NICHD.]

Perceptual learning of talker-specific vowel space

Previous research suggests that as listeners become familiar with a speaker’s vocal style, they are better able to understand that speaker. This study investigated one possible mechanism by which this talker familiarity benefit arises. Listeners’ vowel spaces were measured using a perceptual discrimination test both before and after they were trained to identify a group of speakers by name. Listeners identified either the same speakers whose vowels they discriminated or a different group of speakers. Differences in the learnability and the intelligibility of the two speaking groups were observed. The speaker group that was harder to identify also had vowels that were harder to discriminate. Changes in the listeners’ vowel spaces were determined by examining multidimensional scaling solutions of their responses during the discrimination tests. All listeners became better at discriminating vowels. However, only listeners who heard different speakers during identification training and vowel discrimination exhibited a shift in their vowel spaces after training. This suggests that encountering new voices in an unrelated, nonlinguistic task acts to alter the perceptual context and may affect the structure of linguistic representation. Together, these results suggest a link between linguistic and nonlinguistic information in representations for spoken language.

Individual talker differences in voice-onset-time.

Individual talkers differ in the acoustic properties of their speech, and at least some of these differences are in acoustic properties relevant for phonetic perception. Recent findings from studies of speech perception have shown that listeners can exploit such differences to facilitate both the recognition of talkers' voices and the recognition of words spoken by familiar talkers. These findings motivate the current study, whose aim is to examine individual talker variation in a particular phonetically-relevant acoustic property, voice-onset-time (VOT). VOT is a temporal property that robustly specifies voicing in stop consonants. From the broad literature involving VOT, it appears that individual talkers differ from one another in their VOT productions. The current study confirmed this finding for eight talkers producing monosyllabic words beginning with voiceless stop consonants. Moreover, when differences in VOT due to variability in speaking rate across the talkers were factored out using hierarchical linear modeling, individual talkers still differed from one another in VOT, though these differences were attenuated. These findings provide evidence that VOT varies systematically from talker to talker and may therefore be one phonetically-relevant acoustic property underlying listeners' capacity to benefit from talker-specific experience.

On learning to recognize spectrally reduced speech: I. The effects of multiple repetitions

In a previous study [Chiu et al., J. Acoust. Soc. Am. 109, 2501 (2001)], normal listerers learned open-set recognition of words in Harvard IEEE sentences that were spectrally reduced to 4 channels using the CIS processing strategy [Shannon et al., J. Acoust. Soc. Am. 104, 2467–2476 (1998)]. Half of the listeners listened to a male talker during training, the other half a female talker. At different points in the training listeners were tested with blocks of IEEE sentences spoken by the familiar talker, blocks of IEEE sentences by the novel talker, blocks of IEEE sentences of the 2 talkers randomly intermixed, and blocks of HINT sentences. In that study, listeners could listen to each sentence during early training for an unrestricted number of times before they were given feedback. In the current study, listeners were allowed to listen to each sentence only once during training before feedback was given. Preliminary data obtained from the current study were largely comparable to those obtained in the previous study. The results suggest that massed repetitions and drills, at least in the context of our experimental conditions, wa have minimal effect on learning to recognize spectrally reduced speech. [Work supported by URC, Univ. of Cincinnati.]

Children's recognition of cartoon voices.

We examined developmental changes in talker recognition skills by assessing 3-, 4-, and 5-year-old children's recognition of 20 cartoon characters' voices. For each participant, the character set was subdivided into more and less familiar talkers based on the participant's ability to name each character. Four- and 5- year-old children recognized more of the voices (81% and 86%, respectively) than did 3-year-olds (61%), although performance of all age groups was well above chance. All groups of children were more accurate at recognizing more familiar than less familiar characters. These results suggest that indexical information about a talker becomes an integral part of the perceptual record in memory and can be used by children at a very young age. These results are important because children's ability to learn vocal sources may be an important aid to the development of spoken word recognition.

Learning to recognize spectrally reduced speech: A cochlear implant simulation study

This study investigated training-related improvement in open-set identification of sentences that were spectrally reduced to four channels using the CIS processing strategy [Shannon et al., J. Acoust. Soc. Am. 104, 2467–2476 (1998)]. Over the course of 11 training blocks, listeners with normal hearing identified Harvard IEEE [IEEE Trans. Audio Electroacoust. 17, 225–246 (1969)] sentences with feedback. Half of the listeners listened to a male talker during training; the other half to a female talker. Listeners were tested at different points with blocks of IEEE sentences spoken by the familiar talker, blocks of IEEE sentences by the novel talker, blocks of IEEE sentences by the two talkers randomly intermixed, and blocks of HINT sentences [Nilsson et al., J. Acoust. Soc. Am. 95, 1085–1099 (1994)]. Preliminary data showed an improvement in sentence identification over the course of training. The data also showed a trend of talker specificity for such improvement, in that sentences produced by the novel speaker were harder to identify. In some instances, random intermixing of talkers led to poorer performance than having just one talker within a testing block. Implications for theories of auditory memory and for practical aspects of training will be discussed. [Work supported by URC, Univ. of Cincinnati.]

Encoding tasks and the processing of perceptual information in young and older adults.

This study examined the degree to which different tasks promote the encoding of the characteristics of a talker's voice in young and older adults, and whether these characteristics encoded in long-term memory facilitate spoken word identification under difficult listening conditions. During the encoding phase, participants were given extensive exposure to the voices of two talkers and performed tasks that focused their attention on either voice characteristics (explicitly or incidentally) or linguistic information. Subsequently, participants identified novel words masked by noise, half of which were spoken by one of the familiar talkers and half by an unfamiliar talker. Young adults identified with greater accuracy words spoken in a familiar voice, whereas older adults benefited from voice familiarity only under instructions that promoted attention to voice characteristics either explicitly or incidentally. Age-related declines in sensory uptake (hearing loss) accounted for most of these task-dependent voice effects.

Effects of hearing words, imaging hearing words, and reading on auditory implicit and explicit memory tests.

In four experiments, we examined the degree to which imaging written words as spoken by a familiar talker differs from direct perception (hearing words spoken by that talker) and reading words (without imagery) on implicit and explicit tests. Subjects first performed a surface encoding task on spoken, imagined as spoken, or visually presented words, and then were given either an implicit test (perceptual identification or stem completion) or an explicit test (recognition or cued recall) involving auditorily presented words. Auditory presentation at study produced larger priming effects than did imaging or reading. Imaging and reading yielded priming effects of similar magnitude, whereas imaging produced lower performance than reading on the explicit test of cued recall. Voice changes between study and test weakened priming on the implicit tests, but did not affect performance on the explicit tests. Imagined voice changes affected priming only in the implicit task of stem completion. These findings show that the sensitivity of a memory test to perceptual information, either directly perceived or imagined, is an important dimension for dissociating incidental (implicit) and intentional (explicit) retrieval processes.

Training Mandarin and Cantonese speakers to identify English vowel contrasts: Long-term retention and effect on production

Synthesized hVd vowel stimuli and naturally produced CVC minimal pairs by multiple talkers were used to train native Mandarin and Cantonese speakers to identify the English /i/–/I/, /u/–/U/, and /E/–/Q/ contrasts. In the pre- and post-tests, subjects took the identification tests on synthesized and natural stimuli, and were also recorded producing the target vowel contrasts. Results showed that subjects relied on duration cues for the /i/–/I/, contrast more consistently than they did for the other two contrasts. Training effectively shifted their attention from duration to spectral cues. Trainees’ perceptual performance on natural tokens improved significantly from pretest to post-test on all three contrasts. Accuracy in generalization to new words produced by new talkers was comparable to new words by familiar talkers. The effect of perceptual learning was retained 3 months later after the training was completed. Improvement in production was observed but performance differences between pre- and post-test did not reach significance. The findings suggest that increased perceptual accuracy in identifying L2 vowel contrasts through perceptual training may not be sufficient for significant improvement in production accuracy. Future studies may look at combination of simultaneous production and perceptual training for better results.

Hearing Aid Benefit in Patients with High-Frequency Hearing Loss

Patients with hearing loss limited to frequencies above 2 kHz are often considered borderline candidates for hearing aids. In this study, we used the Profile of Hearing Aid Benefit to access 134 patients' perceived benefit with a variety of linear hearing aids, some more capable than others at achieving prescribed frequency gain targets. We also sought to explore various audiologic and subject factors that might have led patients to report different degrees of success or failure with their hearing aids. Results demonstrate that subjects with hearing loss limited to frequencies above 2 kHz benefit significantly from amplification. However, the amount of benefit reported is mostly unrelated to the hearing aid gain and frequency response. Of numerous audiologic and demographic factors explored in the present study, the number of hours of hearing aid use per day turned out to be the most important single factor that was significantly related to the amount of reported hearing aid benefit. However, the predictive value of knowing how many hours per day subjects wore their aids, or any other combination of factors explored, was quite limited and only accounted for a small amount of the variability observed in user benefit.