Perceptual Assimilation Model Research Articles

Relating assimilation data to identification data in second language learners

Commonly cited models of bilingual phonology, e.g., the Speech Learning Model and the Perceptual Assimilation Model, project hypotheses about second language (L2) developmental patterns based on hypothetical assimilation patterns between categories in the learner’s first language (L1) and L2, with the addition of a learning component which differentiates an L2 and L1 system. This paper relates two experiments with two participant groups, one native Korean, and one native Taiwan Mandarin. Both groups identify English obstruents /p b t d f v θ ð/ in four prosodic positions (onset, coda, and intervocalic pre-stress and post-stress) using their native non-Roman graphemes in the first experiment, and using English labels in the second. The assimilation results generate predictions for discrimination performance in the second experiment, assuming only the L1 categories. The two groups show large differences in assimilation pattern due largely to the non-sibilant fricative /f/ in Mandarin, in opposition to the Korean system which has only non-sibilant /h/. Analyses reveal a strong correlation between L2 discrimination patterns and predictions based solely on the L2-L1 assimilation results, suggesting that the perceptual system of L2 learners can be surprisingly well-captured as a single perceptual system with a bilingual array of segmental categories.

Categorization and discrimination of Mandarin lexical tones by naïve English listeners

Unlike tone languages such as Mandarin, English lacks tones at the sub-lexical level. Accordingly, English listeners have difficulty perceptually assimilating tones as categorized or uncategorized native segments (Perceptual Assimilation Model, PAM: Best, 1995). While English listeners can categorize the four lexical tones of Mandarin, i.e., level contour, rising, dipping, and falling, when given question, statement, exclamation, and uncertainty intonations as category choices (So & Best, 2011, 2014), this does not address tone assimilation at the segmental level. We reasoned that they might assimilate tones as non-assimilable nonspeech patterns if given visual icons as tone category choices (flat, rising, dipping, and falling lines, respectively), with no reference being made to English intonation categories. Accordingly, 76 monolingual English listeners (M age = 24.85 years, 50 females) were set two tasks: to use visual icons to categorize Mandarin tones in naturally produced tone-words (/ga, ti, tu, pu/ × 4 tones) and to discriminate all six pairwise tone contrasts. All tone pairs showed ceiling-level discrimination, and listeners split their categorizations of falling and level stimuli between the falling and flat icons, suggesting that when given visual icons, tone-naïve English listeners perceive Mandarin tones as nonspeech acoustic patterns, which is consistent with PAM’s non-assimilation predictions.

Bilingual phonological contrast perception: The influence of Quanzhou Southern Min on Mandarin non-sibilant fricative discrimination.

This study explores the discrimination of Mandarin non-sibilant fricatives by bilingual speakers (N = 40) of Quanzhou Southern Min (L1) and Mandarin (L2) in different phonological contexts, including rounded vowels and the glide [w]. The results of the ABX discrimination task indicate significant contextual effects of the following sound, in line with predictions based on the Perceptual Assimilation model (PAM) [Best (1995). J. Phon. 20(3), 305-330]. Additionally, the observed result could not be fully explained by the acoustic distance between stimuli, and discrimination ability was better for speakers with more exposure to and use of Mandarin.

Cognitive factors in Thai-naïve Mandarin and Vietnamese speakers’ imitation of Thai lexical tones

The present study examined how native phonological and phonetic factors in non-native speech perception (Perceptual Assimilation Model [PAM]: Best, 1995) affect non-native imitation of Thai tones by Thai-naïve Mandarin and Vietnamese participants, and how memory load and stimulus variability shift the balance between phonological versus phonetic modes (Automatic Selective Perception model [ASP]: Strange, 2011) in imitation. Although overall imitation was quite good, native phonological influences, as reflected in Categorised versus Uncategorised assimilation types in a prior perception study with the same participants (Chen, Antoniou, & Best, 2023), constrained non-native tone imitations. Residual perceptual sensitivity to phonetic differences between the target stimuli and native tones, as reflected in percent choice and goodness ratings in assimilation, also affected imitation. Effects of stimulus variability and memory load were restricted and interacted with specific tones for each participant group. Imitations were generally more accurate under low memory load, constant talker and vowel conditions, consistent with a more phonetic mode of perception. Imitation accuracy decreased under high memory load, variable talker and vowel conditions, consistent with a more phonological mode of perception. Results support the PAM and ASP accounts of native phonological and phonetic effects in non-native perception and extend them to non-native tone imitation.

Prosodic location modulates listener’s perception of novel German sounds

<strong>This is an accepted article with a DOI pre-assigned that is not yet published.</strong> Interaction of sounds on the melodic tier (segments) with prosodic and phonotactic structure (syllabic context) in cross-language perception is not explicitly addressed by models of second language phonology (e.g., Perceptual Assimilation Model: Best, 1995). At initial stages of foreign language exposure, learners rely on position-specific phonetic detail more than native speakers or advanced learners, thus mappings according to prosodic and phonotactic context are a crucial factor in early interlanguage phonological development. In a perceptual assimilation experiment, we manipulated syllable position (onset vs. coda) and phonotactic complexity (simple vs. complex codas) in phonotactically similar languages for auditory presentation of six German obstruents (i.e., familiar [h k ʃ] and novel [ç x p͡f]) to native speakers of American English who had no previous exposure to German. By means of weighted proportions (Park & de Jong, 2008) and overlap scores (Levy, 2009), we found that [h k ʃ p͡f] mapped categorically to English orthographic categories <h>, <k>, <sh>, and <f>, respectively, in all positions, whereas the novel fricatives [ç x] exhibited distinct mapping patterns from each other, from other sounds, and according to syllable position. These results demonstrate profound influences of both prosodic and phonotactic contexts on perceptual assimilation of novel sounds.

Difficulties in decoupling articulatory gestures in L2 phonemic sequences: the case of Mandarin listeners’ perceptual deletion of English post-vocalic laterals

Nonnative or second language (L2) perception of segmental sequences is often characterised by perceptual modification processes, which may "repair" a nonnative sequence that is phonotactically illegal in the listeners' native language (L1) by transforming the sequence into a sequence that is phonotactically legal inthe L1. Often repairs involve the insertion of phonetic materials (epenthesis), but we focus, here, on the less-studied phenomenon of perceptual deletion of nonnative phonemes by testing L1 Mandarin listeners' perception of post-vocalic laterals in L2 English using the triangulating methods of a cross-language goodness rating task, an AXB task, and an AX task. The data were analysed in the framework of the Perceptual Assimilation Model (PAM/PAM-L2), and we further investigated the role of L2 vocabulary size on task performance. The experiments indicate that perceptual deletion occurs when the post-vocalic lateral overlaps with the nucleus vowel in terms of tongue backness specification. In addition, Mandarin listeners' discrimination performance in some contexts was significantly correlated with their English vocabulary size, indicating that continuous growth of vocabulary knowledge can drive perceptual learning of novel L2 segmental sequences and phonotactic structures.

Development of perceptual similarity and discriminability: the perception of Russian phonemes by Chinese learners

This study explored the perceptual assimilation and discrimination of Russian phonemes by three groups of Chinese listeners with differing Russian learning experience. A perceptual assimilation task (PAT) and a perceptual discrimination test (PDT) were conducted to investigate if/how L1-L2 perceptual similarity would vary as a function of increased learning experience, and the development of assimilation-discrimination relations. The PAT was analyzed via assimilation rates, dispersion K' values, goodness ratings and assimilation patterns. Results revealed an intriguing phenomenon that the perceived Mandarin-Russian similarity first increased from naïve listeners to intermediate learners and then decreased slightly in relatively advanced learners. This suggests that L1-L2 perceptual similarity is subject to learning experience and could follow a potential "rise and fall" developmental pattern. The PDT results were mostly in line with the assimilation-discrimination correspondence with more experience bringing out better discriminability in general. Yet the overall sensitivity d' values from the Chinese groups were relatively low, implying acoustic/articulatory effects on L2 discriminability aside from perceptual assimilation. The results were discussed under the frameworks of L2 Perceptual Assimilation Model, Speech Learning Model and L2 Linguistic Perception Model.

Why Aren't All Cantonese Tones Equally Confusing to English Listeners?

English listeners often struggle to perceive tones, but some are easier than others. This study examined these phenomena grounded in the feature weighing perspective (FWP) and the Perceptual Assimilation Model for Suprasegmentals (PAM-S). Forty-seven English and Cantonese listeners completed 4,212 trials of Cantonese tone discrimination and sequence recall tasks. The English listeners showed asymmetrical perceptual patterns of discrimination but not sequence recall. Specifically, these English listeners discriminated T1-T5, T3-T5, and T4-T5 more accurately than T1-T4, T3-T4, and T1-T3. However, they recalled the contour tone and level tone sequences with similar accuracies. Results of the discrimination task aligned with the predictions of PAM-S but not FWP. However, results of the sequence recall task did not support PAM-S. Together, these results suggest that PAM-S only applies to simple discrimination, not abstract phonological processing with a high memory load.

Phonological and phonetic contributions to perception of non-native lexical tones by tone language listeners: Effects of memory load and stimulus variability

The present study examined native language phonological and phonetic factors in non-native lexical tone perception by tone language listeners, manipulating memory load and stimulus variability to bias listeners towards a more phonological or more phonetic mode of perception. Mandarin and Vietnamese listeners categorised the five Thai lexical tones to their native tones, and discriminated five selected Thai tone contrasts that were predicted by the Perceptual Assimilation Model (PAM, Best, 1995) to be discriminated differently. Categorisation responses showed more phonologically-based patterns under high than low memory load but were unaffected by talker and vowel variability, whereas discrimination accuracy was reduced by talker and vowel variability but not by memory load. Phonological factors indicated by type of categorisation and category overlap generally predicted the discrimination of non-native tone contrasts in line with PAM principles. Phonetic factors reflected in category overlap scores and fit index difference scores predicted variations in discriminating contrasts of the same contrast categorisation type. These findings uphold the extension of PAM principles to non-native tone perception by native listeners of other tone languages. Native phonological and phonetic contributions to non-native speech perception differ between categorisation and discrimination tasks, as reflected in differential modulation by memory load and stimulus variability.

The Categorization of L3 Vowels Near First Exposure by Spanish-English Bilinguals

The present study examined the predictions the Perceptual Assimilation Model in the context of naïve bilingual speakers while also considering whether the predictions of third language (L3) models of morphosyntax could be extended to L3 phonology. In particular, it was asked whether several groups of Spanish-English bilinguals (constituting a fully combined design) would categorize sounds in two unknown languages, French and German, using their first language (L1) categories, second language (L2) categories, or a combination of both. 199 participants took part in the study, who made up 4 total groups: L1 English–L2 Spanish (n = 55), L1 Spanish–L2 English (n = 59), English monolingual (n = 59) and Spanish monolingual (n = 29). The participants completed a vowel categorization task, where they were asked to match four vowel sounds in French and German to their existing English and Spanish categories. The results of a series of Bayesian Multinomial regression models suggested that bilinguals categorize L3 vowels using both L1 and L2 categories according to the acoustics of the input. There was no evidence of a clear bias for either the L1 or L2 when an L3 vowel exists in both the L1 and L2. Additionally, the bilingual English participants differed from English monolinguals in the their categorization of new language sounds. These results have implications for both the PAM-L2 and L3 models, by showing that the language learners are not solely guided by their native language, and have access to both L1 and L2 categories when accounting for novel language sounds.

The Perception of English Vowels by Kurdish EFL Learners

This paper investigates English vowel perception in a formal classroom setting by Central Kurdish (CK) learners of English (i.e. EFL learners at university level in The Kurdistan Region of Iraq). Ten English vowels were used as stimuli: five monophthongs with similar qualities but different quantities. The participants included 30 first year English majors. They were tested while performing a discrimination task. The task to discriminate 50 pairs of RP English vowel contrasts was an AX style task. The RP vowels differed from the CK vowels in both quality and quantity. As stated by the Perceptual Assimilation Model L2, the results demonstrated a variety of assimilation types (PAM-L2). It was more difficult to distinguish between two sets of similar vowels. Furthermore, closer vowel contrasts in the vowel space were more difficult to distinguish. To the best of our knowledge, no previous research has looked into Kurdish EFL students' perceptions of English vowels. The perception of English vowels by these Kurdish English learners mostly agreed with PAM's predictions, and the results of the discrimination task ranged from excellent to poor.

Sketching the Landscape of Speech Perception Research (2000-2020): A Bibliometric Study.

Based on 6,407 speech perception research articles published between 2000 and 2020, a bibliometric analysis was conducted to identify leading countries, research institutes, researchers, research collaboration networks, high impact research articles, central research themes and trends in speech perception research. Analysis of highly cited articles and researchers indicated three foundational theoretical approaches to speech perception, that is the motor theory, the direct realism and the computational approach as well as four non-native speech perception models, that is the Speech Learning Model, the Perceptual Assimilation Model, the Native Language Magnet model, and the Second Language Linguistic Perception model. Citation networks, term frequency analysis and co-word networks revealed several central research topics: audio-visual speech perception, spoken word recognition, bilingual and infant/child speech perception and learning. Two directions for future research were also identified: (1) speech perception by clinical populations, such as hearing loss children with cochlear implants and speech perception across lifespan, including infants and aged population; (2) application of neurocognitive techniques in investigating activation of different brain regions during speech perception. Our bibliometric analysis can facilitate research advancements and future collaborations among linguists, psychologists and brain scientists by offering a bird view of this interdisciplinary field.

이집트인 학습자의 한국어 모음 지각과 산출*

This study aims to discuss how Egyptian learners of Korean perceive and categorize Korean vowels, how Koreans perceive Korean vowels they pronounce, and how Egyptian learners’ Korean vowel categorization affects their perception and production of Korean vowels. In Experiment 1, 53 Egyptian learners were asked to listen to Korean test words pronounced by Koreans and choose the words they had listened to among 4 confusable words. In Experiment 2, 117 sound files (13 test words×9 Egyptian learners) recorded by Egyptian learners were given to Koreans and asked to select the words they had heard among 4 confusable words. The results of the experiments show that “new” Korean vowels that do not have categorizable ones in Egyptian Arabic easily formed new categories and were therefore well identified in perception and relatively well pronounced, but some of them were poorly produced. However, Egyptian learners poorly distinguished “similar” Korean vowels in perception, but their pronunciation was relatively well identified by native Koreans. Based on the results of this study, we argued that the Speech Learning Model (SLM) and Perceptual Assimilation Model (PAM) explain the L2 speech perception well, but they are insufficient to explain L2 speech production and therefore need to be revised and extended to L2 speech production.

Examination of Korean stop perception in Quebec French listeners through the lens of assimilation overlap.

This study assessed the perceptual assimilation model (PAM) predictions about assimilation types and discrimination performance through the lens of assimilation overlap in Quebec French listeners' perception of nine non-native Korean stop consonants. The consonants varied in voicing (fortis, lenis, and aspirated) and place of articulation (labials, coronals, and velars). In the identification experiment, the Korean three-way voicing contrasts were found to undergo an assimilation overlap to correspond to the French two-way equivalent contrasts across places of articulation. In the discrimination experiment, assimilation overlap tended to hinder detection of non-native speech distinctions, which is in line with the PAM-based suggestion.

Neurophysiology of non-native sound discrimination: Evidence from German vowels and consonants in successive French–German bilinguals using an MMN oddball paradigm

Abstract The present electroencephalographical multi-speaker MMN oddball experiment was designed to study the phonological processing of German native and non-native speech sounds. Precisely, we focused on the perception of German /ɪ-iː/, /ɛ-ɛː/, /a-aː/ and the fricatives [ʃ] and [ç] in German natives (GG) and French learners of German (FG). As expected, our results showed that GG were able to discriminate all the critical vowel contrasts. In contrast, FG, despite their high L2 proficiency level, were only marginally sensitive to vowel length variations. Finally, neither GG nor FG discriminated the opposition between [ʃ] and [ç], as revealed by the absence of MMN response. This latter finding was interpreted in terms of low perceptual salience. Taken together, the present findings lend partial support to the Perceptual Assimilation Model for late bilinguals (PAM-L2) for speech perception of non-native phonological contrasts.

CAN AUDIO-VISUAL TRAINING EQUALLY AFFECT PHONEMIC AND PHONETIC CONTRASTS? AN EXAMPLE OF L2 FRICATIVE PRODUCTION

The paper explores the effect of audio-visual perceptual training on Serbian EFL learners’ production of novel phonemic and phonetic contrasts in L2, specifically focused on fricatives. Hence, the paper aims at discovering whether audio-visual training has equal effects at phonemic and phonetic levels, and also, whether the effect is the same at two different age/proficiency levels, 6th grade primary and 4th grade secondary school. In order to explore the phonemic level we concentrated on interdental fricatives, and for the phonetic level differences sibilant contrasts were included, following the predictions of the Perceptual Assimilation Model (Best 1994) and Speech Learning Model (Flege 1995). The testing for relevant acoustic information was per- formed prior to and immediately following the experimental period, when all the participants were recorded pronouncing a prepared sentence list containing target sounds. It consisted of measuring spectral moments, frication duration and comparison of spectrograms. The results of the audio-visual phonetic training proved especially beneficial for phonemic contrasts, i.e. interdental fricatives for both levels of age/proficiency, while sibilant contrasts showed insignificant progress. The age/proficiency level did not appear to be a significant predictor of the effect of audio-visual training. Along with the empirical results, the paper likewise presents pedagogical implications important for pronunciation teaching and highlights the significance of phonetic training in the Serbian EFL context in particular.

Perceptual realization of Greek consonants by Russian monolingual speakers

Nonnative sound perception might be challenging for adult listeners since they attune from a very young age to the phonological aspects of their native language and, thus, every nonnative sound is filtered through their first language. The present study investigates the perception of Greek consonants in both Consonant-Vowel (CV) and Vowel-Consonant (VC) syllable context by Russian monolingual speakers. To this purpose, 16 Russian speakers aged 19–26 who are students in a University in Moscow and have no knowledge of Greek participated in the study. The participants were tested in an assimilation task in which they were asked to assimilate Greek consonants to their native language phonological categories and in an AXB discrimination task to examine their ability in discriminating nonnative consonantal contrasts. The predictions of the study were developed using the framework of the Perceptual Assimilation Model (PAM). In the assimilation task, the Russian speakers assimilated, as expected, the Greek consonants [t d g x] to the very similar Russian phonological categories [t d g x]. The Greek consonants [θ ð] were merged with the Russian categories [f z] respectively, while the Greek [ç] fell into the Russian phonological category [xj]. By contrast, the Greek consonant [ɟ] was not perceived as an instance of any phonological category of the listeners’ first language. With respect to the discrimination task, the discrimination scores of the Greek contrasts [θ]-[t], [ð]-[d], [ɟ]-[g], and [ç]-[x] ranged from very good to excellent. The findings indicate that Russian speakers assimilated consonants that are not present in their first language in different phonological categories than those proposed by the literature, and that the feature of consonant palatalization that is present in Russian, assisted the listeners to more consistently identify the Greek palatal fricatives. Moreover, the assimilation of Greek consonants differed in some cases for CV vs. VC context and the discrimination of one Greek contrast was different in CV vs. VC context. In general, the results demonstrate that acoustic features found in the speakers’ first language interfered with the perception of nonnative consonants, and that the assimilation of nonnative fricatives (i.e., [θ ð]) to Russian fricative categories (i.e., [f z]) can be explained by the conformation of the speakers’ native language to the faithfulness constraint, which led the speakers to preserving the continuant feature.

Native phonological and phonetic influences in perceptual assimilation of monosyllabic Thai lexical tones by Mandarin and Vietnamese listeners

A cross tone-language perceptual assimilation study investigated native categorisations and goodness ratings of non-native Thai tones by Thai-naive listeners differing in their native tone systems: Mandarin, Northern Vietnamese and Southern Vietnamese. We derived hypotheses from the Perceptual Assimilation Model (PAM: Best, 1995), which considers both native phonological and phonetic influences on perceptual assimilation of non-native speech contrasts. Mandarin listeners reliably categorised the Thai mid level tone to their single native level tone category, reflecting a native phonological effect, but they also showed high residual phonetic sensitivity to differences between the non-native tone and the native tone it was assimilated to, indicated by low category-goodness ratings. Native phonological and phonetic differences in tones of the two Vietnamese dialects also affected perceptual assimilation of the Thai high level and rising tones. In addition, categorisation responses were faster overall for Categorised than Uncategorised assimilations, revealing the processing cost of perceptual uncertainty due to phonological competition among and/or phonetic discrepancies from multiple native categories. This indicates, furthermore, a more focused and thus stronger native phonological contribution for Categorised than Uncategorised assimilations. PAM principles thus extend to non-native tone assimilations and indicate the importance of both native phonological and phonetic contributions to non-native speech perception.

Discrimination of four Canadian-French vowels by native Canadian-English listeners

Discrimination of Canadian French /y/, /u/, /ɑ/, and /e/ by native Canadian-English listeners was investigated to determine if patterns found in standard varieties of French (as explained by the Perceptual Assimilation Model) could be replicated in Canadian French. Front-rounded /y/ paired with /u/ was the focus of investigation, as well as other (control) pairs. It was found that /y/-/u/ was the most difficult to discriminate as compared to other pairs, but that listeners were sensitive to the contrast, which replicates previous findings in European French. Results are explained as a mix of instances of single-category and category-goodness assimilation patterns.

Perception of English Tense and Lax Vowels by Young Dialect Speakers and its Pedagogical Implication

This study attempts to investigate the perception of English tense and lax vowels /i, ɪ, u:, ʊ, eɪ, ɛ, oʊ, ɔ/ by two regional dialect Korean speakers focusing on the phonological and phonetic distinction. Their perceptual patterns are analyzed based on the Perceptual Assimilation Model. For this study, two perceptual tasks, the AX discrimination task and an identification task, were carried out with 18 Kyunggi dialect speakers and 12 North Kyungsang dialect speakers by using different sets of 80 tokens. The major results indicate that: (1) in phonetic distinction, there was no major difference in discriminating tense and lax vowels between regional dialect speakers; (2) in phonological distinction, a significant difference was detected in /i-ɪ/ pair in North Kyungsang dialect speakers; (3) Both groups showed the poorest performance in perceiving /u:-ʊ/ in phonetic and phonological distinction, specifically lower in phonological distinction; and (4) Employing this result of the L2 perceptual category into PAM, it can be explained that each regional dialect group uses different parameters of category goodness in L2 acquisition. Based on this analysis, the pedagogical implication is provided.