Perception Of Foreign-accented Speech Research Articles

Orthographic information facilitates discrimination of native and foreign-accented speech

Previous research on the perception of foreign-accented speech has demonstrated that providing orthographic transcriptions of auditory stimulus words influences accentedness ratings of the talker. Specifically, foreign-accented talkers are rated as having less accented speech in favorable listening conditions when orthographic information is present. Cochlear implant users show poor identification and discrimination of foreign-accented speech relative to listeners with normal hearing. In the current study, we examined whether orthographic information facilitates the discrimination of native and foreign-accented (non-native) speech under cochlear-implant simulation. Participants were presented with native or foreign-accented sentences through an eight-channel noise vocoder with or without matching text. They were asked to determine whether the sentence was spoken by a native or non-native talker. We hypothesized that the presence of matching text would increase identification accuracy and decrease reaction time. Consistent with our predictions, participants more accurately and more quickly identified whether sentences were spoken by a non-native talker in the presence of matching text compared to performance in conditions with no text. These results suggest that the presence of orthographic information may facilitate indexical, non-linguistic perception under cochlear-implant simulation. Future work will determine whether these results may extend to cochlear implant users.

Effects of Spectral Envelope and Fundamental Frequency Shifts on the Perception of Foreign-Accented Speech.

To investigate the role of spectral pattern information in the perception of foreign-accented speech, we measured the effects of spectral shifts on judgments of talker discrimination, perceived naturalness, and intelligibility when listening to Mandarin-accented English and native-accented English sentences. In separate conditions, the spectral envelope and fundamental frequency (F0) contours were shifted up or down in three steps using coordinated scale factors (multiples of 8% and 30%, respectively). Experiment 1 showed that listeners perceive spectrally shifted sentences as coming from a different talker for both native-accented and foreign-accented speech. Experiment 2 demonstrated that downward shifts applied to male talkers and the largest upward shifts applied to all talkers reduced the perceived naturalness, regardless of accent. Overall, listeners rated foreign-accented speech as sounding less natural even for unshifted speech. In Experiment 3, introducing spectral shifts further lowered the intelligibility of foreign-accented speech. When speech from the same foreign-accented talker was shifted to simulate five different talkers, increased exposure failed to produce an improvement in intelligibility scores, similar to the pattern observed when listeners actually heard five foreign-accented talkers. Intelligibility of spectrally shifted native-accented speech was near ceiling performance initially, and no further improvement or decrement was observed. These experiments suggest a mechanism that utilizes spectral envelope and F0 cues in a talker-dependent manner to support the perception of foreign-accented speech.

Effects of pitch contour and speaking rate on perception of foreign-accented speech

Perception of foreign accent is typically studied using an accentedness rating task. For example, native English listeners rate the degree of accentedness in sentences produced by non-native English speakers. However, in the past studies, it has been unclear that on what criteria participants used to judge accentedness. Here, native English speakers rated the accentedness of Korean-accented English sentences on a scale from 1 (strong accent) to 9 (little to no accent). Participants rated sentences that were unmodified or had one acoustic property removed. In one block, pitch contours of sentences were flattened and set to their mean values. In another block, speaking rates were set to the grand mean of all speaking rates (3.8 syllables/second). This way, changes in accentedness ratings across unmodified and modified sentences were attributable to the acoustic property that was removed. Accentedness ratings were not systematically influenced by manipulations of pitch contours but were influenced by speaking rate manipulations. Increasing the speaking rate (to 3.8 syllables/second) made sentences sound less accented than their unmodified versions; decreasing the speaking rate made sentences sound more accented than their unmodified versions. Results suggest that the speaking rate directly contributes to ratings of foreign accentedness.

The perception of foreign-accented speech: The relative contribution of segments and intonation

The perception of foreign-accented speech: The relative contribution of segments and intonation

Identification of Russian accented Finnish by native and non-native listeners with and without Finnish proficiency


 
 
 The study focuses on how different groups of listeners, that is native Finnish speakers (n = 18), non-native learners of Finnish (n = 12) and non-native non-learners of Finnish (n = 18), judge samples (n = 80) of Russian accented Finnish in an auditory experiment. The samples are read-aloud phrases of three Finnish speakers and three L1 Russian beginner learners of Finnish who were recorded three times at six-month intervals during their residence in Finland. The results show that the listener groups differ significantly from each other in the ability to identify the Russian accented samples. In addition, all the listener groups reported to have paid more attention to prosodic and segmental cues than speech rate. Finally, we conclude by considering implications of the study to further longitudinal studies on perception of foreign accented speech.
 
 

Not all errors are the same: ERP sensitivity to error typicality in foreign accented speech perception

Intercultural communication has become more and more frequent in the recent globalized society. When native listeners try to understand non-native speakers, they have to deal with different types of grammatical errors, some being frequently encountered and others being less common. The present Event-Related Potential (ERP) study investigated how native listeners process different types of morphosyntactic errors in foreign accented speech and whether they are sensitive to error typicality. Spanish natives listened to Spanish sentences in native and foreign (English) accent. ERPs were recorded in response to morphosyntactic violations that were commonly (gender errors) encountered in English accented Spanish or not (number errors). Although sentence comprehension accuracy did not differ across accents, the ERP responses changed as a function of accent and error type. In line with previous studies, gender and number violations in native accented speech elicited LAN-P600 responses. When speech was uttered by foreign speakers, number violations (uncommon errors) showed a P600 effect, while gender violations (common errors) did not elicit late repair processes (reflected by the P600) but an N400 effect. The present results provide evidence that the neural time course of parsing depends not only on speaker's accent, but also on input error typicality.

Audiovisual benefit in the perception of foreign-accented speech by cochlear-implant users

When visual and auditory speech cues are presented together, listeners typically obtain an audiovisual (AV) benefit, or a boost in speech perception accuracy compared to auditory-only (AO) or visual-only (VO) presentations. Visual cues are particularly important for the speech perception of cochlear-implant (CI) users, who show a greater AV benefit than normal-hearing (NH) listeners. However, whether CI users can utilize visual cues for an AV benefit when the speaker has a foreign accent is unknown. Accented speech can alter auditory (primarily temporal) and visual cues, and is significantly more difficult for CI users in AO listening conditions. We investigated the AV benefit in CI users for unaccented and accented speech, presenting IEEE sentences in VO, AO, and AV conditions. The sentences were spoken by one native English speaker and one non-native English speaker who is a native Spanish-speaker from Peru. Preliminary results reveal that CI users show AV benefits in both unaccented and accented conditions, with substantially larger AV benefits for accented speech. Although visual cues alone may be insufficient for speech perception, CI users may necessitate more reliance on visual cues when presented with auditory cues that have been altered in accented speech.

Children's Use of Semantic Context in Perception of Foreign-Accented Speech.

The purpose of this study is to evaluate children's use of semantic context to facilitate foreign-accented word recognition in noise. Monolingual American English speaking 5- to 7-year-olds (n = 168) repeated either Mandarin- or American English-accented sentences in babble, half of which contained final words that were highly predictable from context. The same final words were presented in the low- and high-predictability sentences. Word recognition scores were better in the high- than low-predictability contexts. Scores improved with age and were higher for the native than the Mandarin accent. The oldest children saw the greatest benefit from context; however, context benefit was similar regardless of speaker accent. Despite significant acoustic-phonetic deviations from native norms, young children capitalize on contextual cues when presented with foreign-accented speech. Implications for spoken word recognition in children with speech, language, and hearing differences are discussed.

The influence of long-term exposure on the perception of foreign-accented speech

We recognize spoken words in our native language with relative ease. Yet, difficulties arise when we encounter a talker with an accent. Short-term lab exposure leads to observable improvements in comprehension of foreign-accented speech. Life-long exposure markedly improves perception of within language variability (i.e. dialects) and refines listeners’ representations. Less is known about the benefits of long-term exposure to foreign-accented speech. We used cross-modal identity priming to investigate if long-term exposure to Chinese-accented English by native speakers of American English would modulate their processing of Chinese-accented speech. We predicted that listeners with long-term exposure to the foreign accent, assumed based on long-term residence in the New York City area, should be faster and more accurate at recognizing Chinese-accented words than listeners without long-term exposure, assumed based on long-term residence in less linguistically diverse areas. Our preliminary results present a surprising finding indicating that the assumed long-term exposure had the opposite effect, where the listeners with long-term exposure to a foreign accent are unexpectedly slower and less accurate than the listeners without long-term exposure. Our results suggest that long-term exposure does affect listeners’ abilities to recognize and represent foreign-accented spoken words.

When prosody kicks in: The intricate interplay between segments and prosody in perceptions of foreign accent

This study examines the relative contribution of prosody and segments in the perception of foreign-accented speech. Although both prosody and segments have previously been shown to contribute to the degree of foreign accentedness, results for their relative contribution have proven inconclusive and little is known about their interaction. We recorded read speech of five German learners of English – with and without previous exposure to the Belfast English accent – and one native speaker of Belfast English. Through acoustic manipulations that allow separation of prosodic and segmental information in the speech signal, we created combinations of native segments with non-native prosody and vice versa. The resulting stimuli were then presented to 60 native English listeners, who rated their foreign accentedness, in order to establish whether the impact of prosody depends on the degree of foreign accent at the segmental level and/or the other way round. Group analyses of the obtained foreign accent ratings are presented, supplemented by phonetic analyses of the manipulated stimuli and individual L2 speakers. Results confirm that whilst both segments and prosody contributed to foreign accent perception, listeners were more influenced by segments than prosody. In addition, it was found that the impact of prosody on perceived foreign accentedness varied depending on the origin of the segments: listeners’ sensitivity to small prosodic differences from the native norm was compromised when mixed with non-native segments, whereas sensitivity to small prosodic differences from the non-native norm was compromised when mixed with native segments. In light of this, we propose that there needs to be a degree of correspondence between segments and prosody for small deviances in prosody to be perceived. The study thus contributes to research on foreign accent perception and suggests that the interplay between segments and prosody in such perceptions is more intricate than previously thought.

Perceptual impact of speech melody hybridization: English and Czech English

The current paper examines the role of intonation in the perception of foreign-accented speech. In order to assess how difficult it is to mentally process native, non-native and modified speech melodies, four conditions were analyzed and compared: native English, native English with Czech melody, Czech English with native melody and Czech English. The method of reaction times measurement in a word monitoring task was employed, in which 108 Czech listeners heard English sentences in the explored conditions and pressed a button when hearing a target word. Speech melody turned out to have a relatively weak but discernible impact on perceptual processing. Interestingly, Czech English proved to be more difficult to process than native English, although the listeners were Czech. The implementation of English F0 contours on Czech English speech slightly alleviated the cognitive load, however, the second hybrid, native English with Czech melody, pointed to the opposite direction. The causes of this discrepancy were investigated, particularly higher degrees of collocability in certain expressions.

Editorial: Current research and emerging directions on the cognitive and neural organization of speech processing.

This Research Topic consists of 14 manuscripts discussing the cognitive and neural organization of speech processing. The contributions are grouped around four themes: (1) Spoken language comprehension under difficult listening conditions; (2) Sub-lexical processing; (3) Sensorimotor processing of speech; (4) Speech production. Seven papers addressed speech perception under challenging listening conditions. Van Engen and Peelle (2014) discuss the effects of processing speech in an unfamiliar regional or foreign accent. They argue that, as perceiving accented speech incurs a processing cost, just like other types of distortions such as background noise, it should also be regarded as representing a challenging listening condition. Neger et al. (2014) focused on plasticity of speech processing in statistical and perceptual learning tasks in aging. They conclude that perceptual and statistical learning share mechanisms of implicit regularity detection, but that the ability to detect statistical regularities is impaired in older adults for fast visual sequences. Dekerle et al. (2014) examined whether speech perception in a multi-speaker background relies on semantic interference between the background and target speaker using a semantic priming paradigm in three experiments. Their results indicate that higher-level linguistic processes such as semantic priming may not be as automatic as commonly thought but are subjected to the limits of cognitive resources such as working memory and attention. Yi et al. (2014) evaluate how processing of foreign-accented speech relates to social cognition. It was concluded that foreign-accented speech perception engages greater activation of neural systems underlying speech perception, and that implicit Asian-foreign association is related to with decreased neural efficiency in early spectrotemporal processing. Vitello et al. (2014) used fMRI to address the question of how semantic ambiguities are resolved during speech comprehension. Straus et al. (2014) examined through literature review whether neural oscillations in the alpha frequency range (~ 10 Hz) act as a neural mechanism to selectively inhibit the processing of noise to improve auditory selective attention to task-relevant speech signals. Ding and Simon (2014) discuss whether cortical entrained activity is related more closely to speech perception or to auditory encoding that is not specific to speech, by reviewing evidence regarding various hypotheses about the functional roles of cortical entrainment to speech. Three papers focused on perception of speech at sub-lexical levels. Deschamps and Tremblay (2014) studied perception of sub-lexical information by examining the neural bases of processing of simple syllables and more complex syllabic structures using fMRI, while Yu et al. (2014) used MEG to study the neural processing of disgust in anterior insula by presenting listeners with syllables with differed intended emotional meanings. Finally Chen et al. (2014) investigated processing of acoustic and phonological information in lexical tones in Mandarin Chinese using EEG. Two papers addressed sensorimotor processing of speech. Komeilipoor et al. (2014) report higher motor excitability as measured using Transcranial Magnetic Stimulation (TMS) in the tongue area during the presentation of meaningful gestures (noun-associated). Sowman et al. (2014) demonstrate that appropriately timed TMS to the hand area, paired with auditorily mediated excitation of the motor cortex, induces an enhancement of motor cortex excitability that lasts beyond the time of stimulation. Two papers focused on speech production. Etchell et al. (2014) provide a review of the stuttering literature and Hernandez-Pavon et al. (2014) present a neuronavigated TMS study exploring the neural locus of aspects of picture naming in healthy participants. This Frontiers Research Topic allows new insights into the neurobiology of speech perception and production, and demonstrates how the field of speech science is now addressing issues at its very core. We believe that the future of the research in the field lies in the effective combination of research methods, e.g., EEG and TMS, or fMRI and EEG, as research will benefit from the strengths of each method. In conclusion, this Research Topic consists of 14 excellent contributions, and we are convinced the Topic will provide readers with novel ideas for future studies that will elucidate the cognitive and neural architecture of speech processing.

Foreign-accented speech perception ratings: a multifactorial case study

Seventy-eight native English speakers rated the foreign-accented speech (FAS) of 24 international students enrolled in an Intensive English programme at a public university in Texas on degree of accent, comprehensibility and communicative ability. Variables considered to potentially impact listeners' ratings were the sex of the speaker, the first language family of the speaker (Asian, Hispanic and Middle-Eastern students participated), the speaker's proficiency level (students were enrolled in low-, intermediate- and advanced-proficiency courses) and listeners' self-reported familiarity (low, medium or high) with FAS. The results of a multifactorial ANOVA and Tukey's pairwise comparisons of means suggest that all variables significantly correlate with listeners' judgements in all three rating areas, which lend further support to previous research. More importantly, the present multifactorial ANOVA identified significant interactions of all variables; this indicates that listeners' perception of FAS, rather than being solely determined by one factor alone, is shaped by a complex interplay of several characteristics of the FAS sample. We discuss each of these interactions in turn and discuss their implications for future research and English-as-a-second-language (ESL) teaching.

English native monolingual and simultaneous English/Spanish bilingual listeners’ perception of foreign accented speech: Cross-language effects on accented speech perception

The current study was designed to explore whether English monolingual listeners (ENM) perceive foreign- accented speech differently from English/ Spanish simultaneous bilingual listeners (ESB) who learned both languages simultaneously at early age. Previous studies suggest that listener’s perception of foreign-accented speech is affected by listener’s L1 phonological systems. When exposed to two languages simultaneously, bilinguals might be able to exploit the phonetic categories of the two languages in speech perception [Best (1994), Goetry and Kolinsky (2000)]. It would be possible that simultaneous exposure to multi-languages at the early age helps SB listeners to tolerate foreign accents in speech more resulting in better understanding of accented speech. It would be also possible that if two phonological systems of SB listeners interact each other resulting in poorer understanding of foreign accented speech than ENM listeners. ENM and SB listeners completed two speech perception tasks: accent ratings of an English passage and identification of English vowels spoken by Korean-native speakers. Results might suggest the effect of language exposure on accented speech perception.

Influence of generational cohort and experience with non-native speakers on evaluation of speakers with foreign-accented speech

This article reports the effect of participants' generational differences and subsequent amount of contact with non-native speakers on the perception of foreign-accented speech in the context of internationalization of Japan. The participants were people in their 50s or 60s who were in variety of occupations. They spent their youth from the 1970s to the 1980s in Japan, when Japanese society went through a rapid change in terms of internationalization. Since then, the number of foreign residents has tripled and non-native speakers are commonly encountered on the street and in media. The participants' perception of speech was compared with that of the younger generation to determine whether the historical period in which people grew up affects their perception. It was found that regardless of the age of native listeners, foreign-accented speech was evaluated less positively than native speech. However, experience of contact with non-native speakers made a difference in some aspects of the judgment by native listeners.

Speaker-independent factors affecting the perception of foreign accent in a second language

Previous research on foreign accent perception has largely focused on speaker-dependent factors such as age of learning and length of residence. Factors that are independent of a speaker's language learning history have also been shown to affect perception of second language speech. The present study examined the effects of two such factors--listening context and lexical frequency--on the perception of foreign-accented speech. Listeners rated foreign accent in two listening contexts: auditory-only, where listeners only heard the target stimuli, and auditory + orthography, where listeners were presented with both an auditory signal and an orthographic display of the target word. Results revealed that higher frequency words were consistently rated as less accented than lower frequency words. The effect of the listening context emerged in two interactions: the auditory + orthography context reduced the effects of lexical frequency, but increased the perceived differences between native and non-native speakers. Acoustic measurements revealed some production differences for words of different levels of lexical frequency, though these differences could not account for all of the observed interactions from the perceptual experiment. These results suggest that factors independent of the speakers' actual speech articulations can influence the perception of degree of foreign accent.

The impact of phonetic dissimilarity on the perception of foreign accented speech

Non-normative speech (i.e., synthetic speech, pathological speech, foreign accented speech) is more difficult to process for native listeners than is normative speech. Does perceptual dissimilarity affect only intelligibility, or are there other costs to processing? The current series of experiments investigates both the intelligibility and time course of foreign accented speech (FAS) perception. Native English listeners heard single English words spoken by both native English speakers and non-native speakers (Mandarin or Russian). Words were chosen based on the similarity between the phonetic inventories of the respective languages. Three experimental designs were used: a cross-modal matching task, a word repetition (shadowing) task, and two subjective ratings tasks which measured impressions of accentedness and effortfulness. The results replicate previous investigations that have found that FAS significantly lowers word intelligibility. Furthermore, in FAS as well as perceptual effort, in the word repetition task, correct responses are slower to accented words than to nonaccented words. An analysis indicates that both intelligibility and reaction time are, in part, functions of the similarity between the talker’s utterance and the listener’s representation of the word.

On the role of phonetic inventory in the perception of foreign-accented speech

The current study investigates the effect of phonetic inventory on perception of foreign-accented speech. The perception of native English speech was compared to the perception of foreign-accented English (Dutch-accented English), with selection of stimuli determined on the basis of phonetic inventory. Half of the stimuli contained phonemes that are unique to English and do not occur in Dutch (e.g., [θ] and [æ]), and the other half contained only phonemes that are similar in both English and Dutch (e.g., [s], [i]). Both word and nonword stimuli were included to investigate the role of lexical status. A native speaker of English and a native speaker of Dutch recorded all stimuli. Stimuli were then presented to 40 American listeners using a randomized blocked design in a lexical decision experiment. Results reveal an interaction between speaker (native English versus native Dutch) and phonetic inventory (unique versus common phonemes). Specifically, Dutch-accented stimuli with common phonemes were recognized faster and more accurately than Dutch-accented stimuli with unique phonemes. Results will be discussed in terms of the influence of foreign accent on word recognition processes.

The perception of foreign-accented speech

The purpose of the present study is to assess the contribution of various phonetic and phonological factors to the perception of global foreign accent. Two native Spanish speakers of fluent but heavily accented English recorded English phrases containing sounds or sequences of sounds whose production is characteristically difficult for native speakers of Spanish. Investigated factors included: those affecting syllable structure (initial epenthetic schwa, non-initial epenthetic schwa (-ed ending)); those affecting vowel quality (vowel reduction, tense-laxness); those affecting consonants (final /s/ deletion, manner (/t∫−∫/), fricative voicing (/z-s/), stop voicing); and those affecting stress (lexical stress and phrasal stress). English-speaking listeners rated extent of foreign accent of the Spanish phrases as originally produced and as edited acoustically. Listeners were sensitive to syllable structure factors, final /s/ deletion, consonant manner, and lexical and phrasal stress, but were not sensitive to voicing differences.