The perception of phonemic contrasts in a non-native dialect

Relative Contributions of Social, Contextual, and Lexical Factors in Speech Processing

This exploratory study examined the simultaneous interactions and relative contributions of bottom-up social information (regional dialect, speaking style), top-down contextual information (semantic predictability), and the internal dynamics of the lexicon (neighborhood density, lexical frequency) to lexical access and word recognition. Cross-modal matching and intelligibility in noise tasks were conducted with a community sample of adults at a local science museum. Each task featured one condition in which keywords were presented in isolation and one condition in which they were presented within a multiword phrase. Lexical processing was slower and more accurate when keywords were presented in their phrasal context, and was both faster and more accurate for auditory stimuli produced in the local Midland dialect. In both tasks, interactions were observed among stimulus dialect, speaking style, semantic predictability, phonological neighborhood density, and lexical frequency. These interactions revealed that bottom-up social information and top-down contextual information contribute more to speech processing than the internal dynamics of the lexicon. Moreover, the relatively stronger bottom-up social effects were observed in both the isolated word and multiword phrase conditions, suggesting that social variation is central to speech processing, even in non-interactive laboratory tasks. At the same time, the specific interactions observed differed between the two experiments, reflecting task-specific demands related to processing time constraints and signal degradation.

One-week phonemic training rebuilds the memory traces of merged phonemes in merged speakers

The phonemic merger is a unique phenomenon which is referred to as acoustically very different phonemes are recognized as the same phoneme. In our previous study, we demonstrated that the merged speakers had lost the ability to discriminate the merged phonemes pre-attentively, as revealed by their failure in mismatch negativity (MMN) elicitation in the oddball stream of the merged phonemes /n/-/l/. In this study, we investigated the recovery of the discrimination ability via phonemic training and found that the merged speakers regained the ability of discriminating merged phonemes pre-attentively, after a 7-day /n/-/l/ phonemic training, as revealed by the reactivation of MMN brain response to the /n/-/l/ phoneme categories. Our finding indicates that separate memory traces of merged phonemes could be rebuilt during the training process.

Are Prosodic Variants Stored in the French Mental Lexicon?

A long-term priming experiment examined the way stress information is processed and represented in French speakers' mind. Repeated prime and target words either matched (/bã'do/ - /bã'do/ "headband") or mismatched their stress pattern (/bãdo/ - /bã'do/). In comparison to a control condition (/maʁ[Formula: see text]/ - /bã'do/), the results showed that matching and mismatching primes were equally effective in facilitating the processing of the target words. Thus, despite the fact that French speakers routinely produce and hear words in their stressed and unstressed versions, this study suggests that stress in French is not integrated into lexical representations.

Subphonemic Variation and Lexical Processing: Social and Stylistic Factors

Different pronunciation variants of the same word can facilitate lexical access, but they may be more or less effective primes depending on their phonological form, stylistic appropriateness, familiarity, and social prestige, suggesting that multiple phonological variants are encoded in the lexicon with varying strength. The current study investigated how subphonemic variation is encoded using a lexical decision task with cross-modal form priming. The results revealed that the magnitude of priming was mediated by stylistic and social properties of the auditory primes, including speaking style, talker dialect, and duration. These interactions provide evidence that phonetically reduced forms and forms that are not socially prestigious are not as robustly encoded in the lexicon as canonical forms and forms produced in prestigious varieties.

A Survey of Phonological Mid Vowel Intuitions in Central Catalan

Catalan, like other Romance languages, has two pairs of phonemic mid vowels (/be/ "well" vs. /bɛ/ "lamb"; /os/ "bear" vs. /ɔs/ "bone"). However, these contrasts do not function like others in the language: they are partially phonologically conditioned, and evidence shows that words may be pronounced with different mid vowels by speakers of the same variety or even by the same speaker. Spanish may influence this instability, as first-language Spanish Catalan-Spanish bilinguals struggle to perceive and produce the contrast. This paper investigates the mid vowel contrasts in an Internet survey of vowel height judgments in 220 words by 146 Central Catalan-speaking individuals who also self-reported their language history. Results confirm that certain phonological contexts condition mid vowel height, typically favoring low mid judgments; where phonological conditioning occurs, speakers judge quality with increased consistency and confidence. Many words lacking phonological conditioning environments, however, are variable across speakers. Bilingualism levels and age have an effect: among Catalan-dominant participants, choice of mid vowel is affected by age, while participants with the highest Catalan dominance have greatest confidence in their intuitions. Variably-judged words are also phonetically variable, indicating a word-specific association between strength of phonological representation and realization.

Rapid adaptation to foreign-accented speech and its transfer to an unfamiliar talker

How fast can listeners adapt to unfamiliar foreign accents? Clarke and Garrett [J. Acoust. Soc. Am. 116, 3647-3658 (2004)] (CG04) reported that native-English listeners adapted to foreign-accented English within a minute, demonstrating improved processing of spoken words. In two web-based experiments that closely follow the design of CG04, the effects of rapid accent adaptation are examined and its generalization is explored across talkers. Experiment 1 replicated the core finding of CG04 that initial perceptual difficulty with foreign-accented speech can be attenuated rapidly by a brief period of exposure to an accented talker. Importantly, listeners showed both faster (replicating CG04) and more accurate (extending CG04) comprehension of this talker. Experiment 2 revealed evidence that such adaptation transferred to a different talker of a same accent. These results highlight the rapidity of short-term accent adaptation and raise new questions about the underlying mechanism. It is suggested that the web-based paradigm provides a useful tool for investigations in speech adaptation.

Introduction to the Special Issue on Advancing Methods for Analyzing Dialect Variation

Documenting and analyzing dialect variation is traditionally the domain of dialectology and sociolinguistics. However, modern approaches to acoustic analysis of dialect variation have their roots in Peterson and Barney's [(1952). J. Acoust. Soc. Am. 24, 175-184] foundational work on the acoustic analysis of vowels that was published in the Journal of the Acoustical Society of America (JASA) over 6 decades ago. Although Peterson and Barney (1952) were not primarily concerned with dialect variation, their methods laid the groundwork for the acoustic methods that are still used by scholars today to analyze vowel variation within and across languages. In more recent decades, a number of methodological advances in the study of vowel variation have been published in JASA, including work on acoustic vowel overlap and vowel normalization. The goal of this special issue was to honor that tradition by bringing together a set of papers describing the application of emerging acoustic, articulatory, and computational methods to the analysis of dialect variation in vowels and beyond.

Effects of Lexical Competition and Dialect Exposure on Phonological Priming

A cross-modal lexical decision task was used to explore the effects of lexical competition and dialect exposure on phonological form priming. Relative to unrelated auditory primes, matching real word primes facilitated lexical decision for visual real word targets, whereas competing minimal pair primes inhibited lexical decision. These effects were robust across two English vowel pairs (mid-front and low-front) and for two listener groups (mono-dialectal and multi-dialectal). However, both the most robust facilitation and the most robust inhibition were observed for the mid-front vowel words with few phonological competitors for the mono-dialectal listener group. The mid-front vowel targets were acoustically more distinct than the low-front vowel targets, suggesting that acoustic-phonetic similarity leads to stronger lexical competition and less robust facilitation and inhibition. The multi-dialectal listeners had more prior exposure to multiple different dialects than the mono-dialectal group, suggesting that long-term exposure to linguistic variability contributes to a more flexible processing strategy in which lexical competition extends over a longer period of time, leading to less robust facilitation and inhibition.

Where do dialectal effects on speech processing come from? Evidence from a cross-dialect investigation

Accented speech has been seen as an additional impediment for speech processing; it usually adds linguistic and cognitive load to the listener's task. In the current study we analyse where the processing costs of regional dialects come from, a question that has not been answered yet. We quantify the proficiency of Basque–Spanish bilinguals who have different native dialects of Basque on many dimensions and test for costs at each of three levels of processing–phonemic discrimination, word recognition, and semantic processing. The ability to discriminate a dialect-specific contrast is affected by a bilingual's linguistic background less than lexical access is, and an individual's difficulty in lexical access is correlated with basic discrimination problems. Once lexical access is achieved, dialectal variation has little impact on semantic processing. The results are discussed in terms of the presence or absence of correlations between different processing levels. The implications of the results are considered for how models of spoken word recognition handle dialectal variation.

Does orthographic training on a phonemic contrast absent in the listener's dialect influence word recognition?

This study examined whether the ability of southern French speakers to discriminate between standard French word forms such as /pike/ and /pikε/ can be improved by a training procedure in which participants were exposed to the orthographic representations of words forming /e/-/ε/ minimal pairs. The results of the training procedure showed that southern French speakers were able to perceive the /e/-/ε/ contrast in word final position when they associated words containing these vowels with their correct spelled form. Further, participants in a priming experiment, which was run immediately after training, no longer showed the priming effect on the trained minimal pairs that they had shown in the pre-test. However, a priming effect on the untrained minimal pairs was still observed immediately after training, showing that this training failed to transfer to untrained items. Finally, the benefits of the training procedure were no longer observed the day after training, since southern French speakers once again showed a priming effect on the trained minimal pair of words in a one day post-test. Implications of these findings for the locus of the difficulties of the southern French speakers with the word-final /e/-/ε/ contrast are discussed.

Glasgow Gloom or Leeds Glue? Dialect-Specific Vowel Duration Constrains Lexical Segmentation and Access

Timing cues are important in many aspects of speech processing, fromidentifying segments to locating word and phrase boundaries. They vary across accents, yet representation and processing of this variation are poorly understood. We investigated whether an accent difference in vowel duration affects lexical segmentation and access. In Glasgow English (GE), /i u e o/ are shorter than in Leeds English (LE), especially for /i u/ before voiced stops and nasals. In a word-spotting experiment, GE and LE participants heard nonsense sequences (e.g. pobegloomezh) containing embedded words (gloom, glue), with segmental qualities intermediate between GE and LE. Critical vowel durations were manipulated according to accent (GE-appropriate vowels shorter than LE-appropriate ones) and phonological context (vowels shortest before voiceless stops < voiced stops/nasals < voiced fricatives). GE participants generally spotted words like gloom more accurately with GE-appropriate than LE-appropriate vowels. LE participants were less accurate than GE participants to spot words like gloom with GE-appropriate vowels, but more likely to spot embeddings like glue. These results were broadly as predicted based on the accent differences, but depended less than expected on the accent-specific phonological constraints. We discuss theoretical implications regarding the representation of duration and the time course of lexical access.

Acoustical analysis of Canadian French word-final vowels in varying phonetic contexts

This study analyzed Canadian French (CF) vowels /i y ø e ɛ o u a/ in word-final position. Of particular interest was the stability of /e-ɛ/; although some dialects of French have merged /e-ɛ/ to /e/ in word-final context, this contrast is maintained in CF. The present study investigated the stability of this contrast in various preceding phonetic contexts and in lexical vs morphological contrasts. Results showed that the contrast was maintained by all four speakers, although to varying degrees.

Influences of listeners' native and other dialects on cross-language vowel perception

This paper examines to what extent acoustic similarity between native and non-native vowels predicts non-native vowel perception and whether this process is influenced by listeners' native and other non-native dialects. Listeners with Northern and Southern British English dialects completed a perceptual assimilation task in which they categorized tokens of 15 Dutch vowels in terms of English vowel categories. While the cross-language acoustic similarity of Dutch vowels to English vowels largely predicted Southern listeners' perceptual assimilation patterns, this was not the case for Northern listeners, whose assimilation patterns resembled those of Southern listeners for all but three Dutch vowels. The cross-language acoustic similarity of Dutch vowels to Northern English vowels was re-examined by incorporating Southern English tokens, which resulted in considerable improvements in the predicting power of cross-language acoustic similarity. This suggests that Northern listeners' assimilation of Dutch vowels to English vowels was influenced by knowledge of both native Northern and non-native Southern English vowel categories. The implications of these findings for theories of non-native speech perception are discussed.

On the intonation of German intonation questions: the role of the prenuclear region

German questions and statements are distinguished not only by lexical and syntactic but also by intonational means. This study revisits, for Northern Standard German, how questions are signalled intonationally in utterances that have neither lexical nor syntactic cues. Starting from natural productions of such 'intonation questions', two perception experiments were run. Experiment 1 is based on a gating paradigm, which was applied to naturally produced questions and statements. Experiment 11 includes two indirect-identification tasks. Resynthesized stimuli were judged in relation to two context utterances, each of which was compatible with only one sentence mode interpretation. Results show that utterances with a finally falling nuclear pitch-accent contour can also trigger question perception. An utterance-final rise is not mandatory. Also, question and statement cues are not restricted to the intonational nucleus. Rather, listeners can refer to shape, slope, and alignment differences of the preceding prenuclear pitch accent to identify sentence mode. These findings are in line with studies suggesting that the utterance-final rise versus fall contrast is not directly related to sentence modality, but represents a separate attitudinal meaning dimension. Moreover, the findings support that both prenuclear and nuclear fundamental frequency (F0) patterns must be taken into account in the analysis of tune meaning.

To what extent do we hear phonemic contrasts in a non-native regional variety? Tracking the dynamics of perceptual processing with EEG

This combined ERP and behavioral experiment explores the dynamics of processing during the discrimination of vowels in a non-native regional variety. Southern listeners were presented with three word forms, two of which are encountered in both Standard and Southern French ([kot] and [kut]), whereas the third one exists in Standard but not Southern French ([kot]). EEG recordings suggest that all of the word pairs were discriminated by the listeners, although discrimination arose about 100ms later for the pairs which included the non-native word form than for those which contained word forms common to both French varieties. Behavioral data provide evidence that vowel discrimination is sensitive to the influence of the listeners' native phonemic inventory at a late decisional stage of processing.

Linguistic processing of accented speech across the lifespan

In most of the world, people have regular exposure to multiple accents. Therefore, learning to quickly process accented speech is a prerequisite to successful communication. In this paper, we examine work on the perception of accented speech across the lifespan, from early infancy to late adulthood. Unfamiliar accents initially impair linguistic processing by infants, children, younger adults, and older adults, but listeners of all ages come to adapt to accented speech. Emergent research also goes beyond these perceptual abilities, by assessing links with production and the relative contributions of linguistic knowledge and general cognitive skills. We conclude by underlining points of convergence across ages, and the gaps left to face in future work.

An ERP investigation of regional and foreign accent processing

This study used event-related potentials (ERPs) to examine whether we employ the same normalisation mechanisms when processing words spoken with a regional accent or foreign accent. Our results showed that the Phonological Mapping Negativity (PMN) following the onset of the final word of sentences spoken with an unfamiliar regional accent was greater than for those produced in the listener's own accent, whilst PMN for foreign accented speech was reduced. Foreign accents also resulted in a reduction in N400 amplitude when compared to both unfamiliar regional accents and the listener's own accent, with no significant difference found between the N400 of the regional and home accents. These results suggest that regional accent related variations are normalised at the earliest stages of spoken word recognition, requiring less top-down lexical intervention than foreign accents.

The Perception and Representation of Segmental and Prosodic Mandarin Contrasts in Native Speakers of Cantonese

Previous research has found that a speaker's native phonological system has a great influence on perception of another language. In three experiments, we tested the perception and representation of Mandarin phonological contrasts by Guangzhou Cantonese speakers, and compared their performance to that of native Mandarin speakers. Despite their rich experience using Mandarin Chinese, the Cantonese speakers had problems distinguishing specific Mandarin segmental and tonal contrasts that do not exist in Guangzhou Cantonese. However, we found evidence that the subtle differences between two members of a contrast were nonetheless represented in the lexicon. We also found different processing patterns for non-native segmental versus non-native tonal contrasts. The results provide substantial new information about the representation and processing of segmental and prosodic information by individuals listening to a closely-related, very well-learned, but still non-native language.

Comparing identification of standardized and regionally valid vowels

PURPOSE

In perception studies, it is common to use vowel stimuli from standardized recordings or synthetic stimuli created using values from well-known published research. Although the use of standardized stimuli is convenient, unconsidered dialect and regional accent differences may introduce confounding effects. The goal of this study was to examine the effect of regional accent variation on vowel identification.

METHOD

The authors analyzed formant values of 8 monophthong vowels produced by 12 talkers from the region where the research took place and compared them with standardized vowels. Fifteen listeners with normal hearing identified synthesized vowels presented in varying levels of noise and at varying spectral distances from the local-dialect values.

RESULTS

Acoustically, local vowels differed from standardized vowels, and distance varied across vowels. Perceptually, there was a robust effect of accent similarity such that identification was reduced for vowels at greater distances from local values.

CONCLUSIONS

Researchers and clinicians should take care in choosing stimuli for perception experiments. It is recommended that regionally validated vowels be used instead of relying on standardized vowels in vowel perception tasks.

Regional differences in the listener's phonemic inventory affect semantic processing: A mismatch negativity (MMN) study

Using the mismatch negativity (MMN) response, we examined how Standard French and Southern French speakers access the meaning of words ending in /e/ or /ε/ vowels which are contrastive in Standard French but not in Southern French. In Standard French speakers, there was a significant difference in the amplitude of the brain response after the deviant-minus-standard subtraction between the frontocentral (FC) and right lateral (RL) recording sites for the final-/ε/ word but not the final-/e/ word. In contrast, the difference in the amplitude of the brain response between the FC and RL recording sites did not significantly vary as a function of the word's final vowel in Southern French speakers. Our findings provide evidence that access to lexical meaning in spoken word recognition depends on the speaker's native regional accent.

Does training on a phonemic contrast absent in the listener's dialect influence word recognition?

Southern French listeners were trained on the word final Standard French /e/-/epsilon/ contrast that does not exist in their dialect. They learned to associate minimal pairs of new words with visual shapes. Although final training session performance was relatively high, the learning did not transfer to a lexical decision task with phonological priming. Thus successful training on a phonemic contrast did not guarantee the efficient use of this contrast in spoken word recognition tasks. These findings are discussed in light of abstractionist and exemplarist models.

Height differences in English dialects: consequences for processing and representation

This study examines the role of abstractness during the activation of a lexical representation. Abstractness and conflict are directly modeled in our approach by invoking lexical representations in terms of contrastive phonological features. In two priming experiments with English nouns differing only in vowel height of their stem vowels (e.g.,pin vs. pan), we compare a conflict versus non-conflict situation across English dialects. Based on differences in the vowel height representation, the conflict occurs in American English, but not in New Zealand English. The results show that there is a lack of priming in the conflict, but not in the non-conflict situation. This is taken as evidence for the claim that lexical access is sensitive to conflicts and non-conflicts between acoustic-phonetic and phonological information. We therefore conclude that discrete phonological features are crucial determiners for successful speech perception, which is in line with abstractionist approaches.