Routes to Lenition: An Acoustic Study

BACKGROUND: Vowel lenition and its link with coarticulation have been the subject of extensive debate in the literature. The aims of the present paper are to demonstrate how vowel lenition and coarticulation are linked in Cypriot Greek (henceforth CG), to determine the nature of vowel lenition, and to illustrate how vowel lenition and coarticulation result from aerodynamic phenomena. METHODOLOGY/PRINCIPAL FINDINGS: Eight speakers were recorded producing utterances ending in either /i/ or /u/. Acoustic measures such as V(1)F2 and stop duration were employed to determine whether lenition of the vowels results in coarticulation with the preceding consonant. Results show that there is extensive stop-vowel coarticulation in CG and that stop production is as variable as vowel production, with full vowels never co-occurring with canonical consonants, indicating the existence of two routes to lenition in CG. CONCLUSIONS/SIGNIFICANCE: These findings suggest that lenition in the final syllable is a consequence of the supralaryngeal articulation coupled with a marginal glottal setting

Cues to Vowels in the Aperiodic Phase of English Plosive Onsets

This thesis addresses the problem of vowel recognition in coarticulatory theory and phonology by assessing how early vowel quality can be recognised from English onset plosives realised with aspiration. Particular attention is paid to aspects of production and perception timing. A gating experiment was used to assess how reliably listeners can recognise English monophthongs. The treatment of coarticulation distinguishes between phonetic and phonological aspects of production and perception, with a clear demarcation between these levels of representation. The results are interpreted through the lens of prosodic phonology, as this framework constrains the grammar more optimally than segmental-phonemic ones and better exemplifies listeners’ sensitivity to the distribution of FPD. Velar and bilabial onsets give rise to significantly more correct responses than alveolars, which require more precise articulations. High vowels are recognised more reliably than low ones. This result is due to their intrinsically shorter duration, making high vowels less variable through time. This perceptual link is proportionate to the total amount of variation in vowel inherent spectral change (VISC), which corresponds to spectro-temporal variation in formant centre frequencies through time in vowel realisations. Nasal rimes give rise to a smaller proportion of correct responses than non-nasal rimes, especially in the context of high and low front vowels: the VISC and changes in vowel height undergone in the context of such articulations, as well as the phonetic consequences of the overall articulatory constellation shape the resulting percept. CVCs with non-nasal rimes give rise to more correct responses than CVVs, despite there being more articulations on-going: the shortness of the vowel in CVCs compensates for this deficit, making perception more robust. Word frequency does not have a significant effect on recognition for any of the syllable types investigated. Overall, a much larger temporal window than the phoneme is required for the robust processing and perceptual integration of speech. Phonemes alone cannot adequately define how the relationship between the phonetic co-extensiveness of different sounds and feature sharing is to be accounted for in speech understanding. Since articulators are in constant motion during production, and consonantal gestures have distinctive coarticulatory influences over vocalic ones, the formant frequencies for both types of sound are in constant flux. This variation reinforces perceptual cohesion and has systematic effects on the mapping of FPD, through which larger structures become audible

An Investigation of Coarticulation Resistance in Speech Production Using Ultrasound

Sound segments show considerable influence from neighbouring segments, which is described as being the result of coarticulation. None of the previous reports on coarticulation in vowel-consonant-vowel (VCV) sequences has used ultrasound. One advantage of ultrasound is that it provides information about the shape of most of the midsagittal tongue contour. In this work, ultrasound is employed for studying symmetrical VCV sequences, like /ipi/ and /ubu/, and methods for analysing coarticulation are refined. The use of electropalatography (EPG) in combination with ultrasound is piloted in the study. A unified approach is achieved to describing lingual behaviour during the interaction of different speech sounds, by using the concept of Coarticulation Resistance, which implies that different sounds resist coarticulatory influence to different degrees. The following research questions were investigated: how does the tongue shape change from one segment to the next in symmetrical VCV sequences? Do the vowels influence the consonant? Does the consonant influence the vowels? Is the vocalic influence on the consonant greater than the consonantal influence on the vowels? What are the differences between lingual and non-lingual consonants with respect to lingual coarticulation? Does the syllable/word boundary affect the coarticulatory pattern? Ultrasound data were collected using the QMUC ultrasound system, and in the final experiment some EPG data were also collected. The data were Russian nonsense VCVs with /i/, /u/, /a/ and bilabial stops; English nonsense VhV sequences with /i/, /u/, /a/; English /aka/, /ata/ and /iti/ sequences, forming part of real speech. The results show a significant vowel influence on all intervocalic consonants. Lingual consonants significantly influence their neighbouring vowels. The vocalic influence on the consonants is significantly greater than the consonantal influence on the vowels. Non-lingual consonants exhibit varying coarticulatory patterns. Syllable and word boundary influence on VCV coarticulation is demonstrated. The results are interpreted and discussed in terms of the Coarticulation Resistance theory: Coarticulation Resistance of speech segments varies, depending on segment type, syllable boundary, and language. A method of quantifying Coarticulation Resistance based on ultrasound data is suggested.sub_shsunpub143_ethesesunpu

Discovering Dynamic Visemes

Abstract This thesis introduces a set of new, dynamic units of visual speech which are learnt using computer vision and machine learning techniques. Rather than clustering phoneme labels as is done traditionally, the visible articulators of a speaker are tracked and automatically segmented into short, visually intuitive speech gestures based on the dynamics of the articulators. The segmented gestures are clustered into dynamic visemes, such that movements relating to the same visual function appear within the same cluster. Speech animation can then be generated on any facial model by mapping a phoneme sequence to a sequence of dynamic visemes, and stitching together an example of each viseme in the sequence. Dynamic visemes model coarticulation and maintain the dynamics of the original speech, so simple blending at the concatenation boundaries ensures a smooth transition. The efficacy of dynamic visemes for computer animation is formally evaluated both objectively and subjectively, and compared with traditional phoneme to static lip-pose interpolation

Production of final alveolar stops in brazilian portuguese/english interphonology

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão. Programa de Pós-Graduação em Letras/Inglês e Literatura correspondenteThis research focuses on the production of final alveolar stops by Brazilian learners of English. In order to investigate that thirty learners from the pre-intermediate level of an English course read a sentence list in English, containing several environment combinations, and a sentence list in BP, containing word-final te and de. Alveolar stops are subject to allophonic processes in BP and serve as a dialect marker. Considering L1 transfer, it is expected that the production of English final alveolar stops is problematic. This production was examined according to three research questions and five hypotheses. The first research question concerned main types of production of final alveolar stops and it was hypothesized that BP learners would produce targetlike, aspirated, palatalized, and epenthesized forms, as well as forms aspirated with vowel epenthesis and palatalized with vowel epenthesis. Even though other types of production were found, the most frequent types of production were the ones predicted by the hypothesis. The second research question dealt with voicing of the target sound, and the hypothesis predicted that the voiced target would be mispronounced more often than its voiceless counterpart. It was found that voicing influence varied according to type of error. The third research question aimed at investigating effects of phonological environment and three hypotheses were formulated. Concerning preceding environment, it was hypothesized that vowel height would carry over to the target facilitating the process of palatalization. The hypothesis was confirmed. Then, following Koerich (2002), it was hypothesized that errors would increase from vowels to consonants, and then to pause in the following environment. This hypothesis was partially confirmed. The last hypothesis concerned sonority relations across syllables and the results pointed to tendencies. To sum up, markedness, phonological environment, and transfer seemed to interact, shaping the production of final alveolar stops in Brazilian Portuguese/English interphonology. Esta pesquisa focaliza a produção de plosivas alveolares em final de sílaba por estudantes brasileiros de inglês. No PB, plosivas alveolares são sujeitas a vários processos alofônicos e servem como um marcador dialetal. Portanto, sua produção em inglês pode tornar-se problemática. Trinta estudantes do nível pré-intermediário de um curso de inglês leram uma lista de sentenças em inglês contendo várias combinações de contexto fonológico e uma lista de sentenças em PB contendo palavras com sílabas finais te e de. A produção de plosivas alveolares finais foi examinada objetivando responder a três questões de pesquisa e investigar cinco hipóteses. (1) A primeira questão tratava dos principais tipos de produção de plosivas alveolares finais e a hipótese era que os participantes produziriam /t, d/ corretos, aspirados, palatalizados, epentetizados, aspirados com epêntese e palatalizados com epêntese. Embora outros tipos de produção foram encontrados, as mais freqüentes foram as previstas pela hipótese. (2) A Segunda questão lidava com vozeamento do som alvo e a hipótese previa que a consoante vozeada seria modificada com maior freqüência. Os resultados mostraram que influência de vozeamento varia conforme o tipo de erro. (3) A terceira questão tinha por objetivo investigar efeitos do ambiente fonológico e foram formuladas três hipóteses: (a) em relação ao ambiente anterior, foi suposto que altura da vogal afetaria altura do alvo promovendo palatalização, a hipótese foi confirmada; (b) seguindo Koerich (2002) foi suposto que erros aumentariam de vogais para consoantes para silêncio no ambiente seguinte ao alvo, a hipótese foi parcialmente confirmada; (c) a última hipótese investigava relações de sonoridade entre sons em diferentes palavras e os resultados apontaram apenas para tendências. Concluindo, marcação, ambiente fonológico e transferência parecem interagir modelando a produção de plosivas alveolares finais na interfonologia do Português do Brasil/Inglês

The acoustics of place of articulation in English plosives

PhD ThesisThis thesis investigates certain aspects of the acoustics of plosives’ place of articulation that have not been addressed by most previous studies, namely: 1. To test the performance of a technique for collapsing F2onset and F2mid into a single attribute, termed F2R. Results: F2R distinguishes place with effectively the same accuracy as F2onset+F2mid, being within ±1 percentage point of F2onset+F2mid at its strongest over most of the conditions examined. 2. To compare the strength of burst-based attributes at distinguishing place of articulation with and without normalization by individual speaker. Results: Lobanov normalization on average boosted the classification of individual attributes by 1.4 percentage points, but this modest improvement shrank or disappeared when the normalized attributes were combined into a single classification. 3. To examine the effect of different spectral representations (Hz-dB, Bark-phon, and Bark-sone) on the accuracy of the burst attributes. The results are mixed but mostly suggest that the choice between these representations is not a major factor in the classification accuracy of the attributes (mean difference of 1 to 1.5 percentage points); the choice of frequency region in the burst (mid versus high) is a far more important factor (13 percentage-point difference in mean classification accuracy). 4. To compare the performance of some traditional-phonetic burst attributes with the first 12 coefficients of the discrete cosine transform (DCT). The motivation for this comparison is that phonetic science has a long tradition of developing burst attributes that are tailored to the specific task of extracting place-of-articulation information from the burst, whereas automatic speech recognition (ASR) has long used attributes that are theoretically expected to capture more of the variance in the burst. Results: the DCT coefficients yielded a higher burst classification accuracy than the traditional phonetic attributes, by 3 percentage points.Economic and Social Research Counc

L2 speech learning of European Portuguese /l/ and /ɾ/ by L1-Mandarin learners: experimental evidence and theoretical modelling

It has been long recognized that the poor distinction between /l/ and /ɾ/ is one of the most perceptible characteristics in Chinese-accented Portuguese. Recent empirical research revealed that this notorious L2 speech learning difficulty goes beyond the confusion between two L2 categories, as L1-Mandarin learners’ acquisition of Portuguese /l/ and /ɾ/ seems to be subject to the interaction among different prosodic positions, speech modalities and representational levels. This thesis aims to deepen our current understanding of this L2 speech learning process, by exploring what constrains the development of L2 phonological categories across syllable positions and how different modalities interact during this process. To achieve this goal, both experimental tasks and theoretical modelling were employed. The first study of this thesis explores the role of cross-linguistic influence and orthography on L2 category formation. In order to elicit cross-linguistic influence directly, a delayed-imitation task was performed with L1-Mandarin naïve listeners. This task examined how the Mandarin phonology parses the Portuguese input ([l], [ɾ]) in intervocalic onset and in word-internal coda position. Moreover, whether orthography plays a role during the construction of L2 phonological representation was tested by manipulating the input types that were given in the experiment (auditory input alone vs. auditory + written input). Our study shows that naïve Mandarin listeners’ responses corroborated with that of L1-Mandarin learners, suggesting that cross-linguistic influence is responsible for the observed L2 prosodic effects. Moreover, the Mandarin [ɻ] (a repair strategy for /ɾ/) occurred almost exclusively when the written form was given, providing evidence for the cross-linguistic interaction between phonological categorization and orthography during the construction of L2 categories. In the second study, we first investigate the interaction between speech perception and production in L2 speech learning, by examining whether the L2 deviant productions stem from misperception and whether the order of acquisition in L2 speech perception mirrors that in production. Secondly, we test whether L2 phonological categories remain malleable at a mid-late stage of L2 speech learning. Two perceptual experiments were performed to test L1-Mandarin learners on their discrimination ability between the target Portuguese form and the deviant form employed in L2 production. Expanding on prior research, in this study, the perceptual motivation for L2 speech difficulties was assessed in different syllable constituents (onset and coda) and at both segmental and suprasegmental levels (structural modification). The results demonstrate that some deviant forms observed in L2 production indeed have a perceptual motivation ([w] for the velarised lateral; [l] and [ɾə] for the tap), while some others cannot be attributed to misperception (deletion of syllable-final tap). Furthermore, learners confused the intervocalic /l/ and /ɾ/ bidirectionally in perception, while in production they never misproduced the lateral (/ɾ/ → [l], */l/ → [ɾ]), revealing a mismatch between two speech modalities. By contrast, the order of acquisition (/ɾ/coda > /ɾ/onset) was shown to be consistent in L2 perception and production. The correspondence and discrepancy between the two speech modalities signal a complex relationship between L2 speech perception and production. To assess the plasticity of L2 categories /l/ and /ɾ/, two groups of L1-Mandarin learners who differ substantially in terms of L2 experience were recruited in the perceptual tasks. Our study shows that both groups behaved similarly in terms of the discrimination performance. No evidence for a role of L2 experience was found. The implication of this null result on L2 phonological development is discussed. The third study of the thesis aims to contribute to bridging the gap between the L2 experimental evidence and formal theories. Adopting the Bidirectional Phonology and Phonetics Model, we formalise some of the experimental findings that cannot be elucidated by current L2 speech theories, namely, the between and within-subject variation in L2 phonological categorization; the interaction between phonological categorization and orthography during L2 category construction; and the asymmetry between L2 perception and production. Overall, this thesis sheds light on the complex nature of L2 phonological acquisition and provides a formal account of how different modalities interact in shaping L2 speech learning. Moreover, it puts forward testable predictions for future research and suggestions for improving foreign language teaching/training methodologies.É bem conhecido o facto de as trocas associadas a /l/ e /ɾ/ constituírem uma das caraterísticas mais percetíveis no português articulado pelos aprendentes chineses. Recentemente, estudos empíricos revelam que a dificuldade por parte dos aprendentes chineses não se restringe à discriminação moderada entre as duas categorias da L2, dado que a aquisição de /l/ e /ɾ/ do português por aprendentes chineses parece estar sujeita à interação entre contextos prosódicos, entre modalidades de fala e entre níveis representacionais diferentes. Esta tese visa aprofundar a nossa compreensão deste processo da aquisição fonológica L2, explorando o que condiciona o desenvolvimento das categorias fonológicas L2 em diferentes constituintes silábicos e de que modo as modalidades interagem durante este processo, recorrendo para tal a tarefas experimentais bem como a formalização teórica. O primeiro estudo averigua o papel da influência interlinguística e o da ortografia na construção das categorias de L2. Para elicitar a influência interlinguística diretamente, uma tarefa de imitação retardada foi aplicada aos falantes nativos do mandarim sem conhecimento de português, investigando assim como a fonologia do mandarim categoriza o input do português ([l], [ɾ]) em ataque simples intervocálico e em coda medial. Para além disso, a influência ortográfica na construção de representações fonológicas em L2 foi examinada através da manipulação do tipo do input apresentado na experiência (input auditivo vs. input auditivo + ortográfico). Os resultados da situação experimental em que os participantes receberam input de ambos os tipos replicaram o efeito prosódico observado na literatura, evidenciando a interação entre categorização fonológica e ortografia na construção das categorias de L2. No segundo estudo, investigamos a interação entre a perceção e a produção de fala na aquisição das líquidas do PE por aprendentes chineses e a plasticidade destas categorias fonológicas, respondendo às questões seguintes: 1) as produções desviantes de L2 resultam da perceção incorreta? 2) a ordem da aquisição em L2 é consistente na perceção e na produção? 3) as categorias da L2 permanecem maleáveis numa fase intermédia da aquisição? Duas tarefas percetivas foram conduzidas para testar a capacidade percetiva dos aprendentes nativos do mandarim em relação à discriminação entre a forma alvo do português e as formas desviantes utilizadas na produção. No presente estudo, a motivação percetiva das dificuldades em L2 foi testada nos constituintes silábicos diferentes (ataque simples e coda) e nos níveis segmental e suprassegmental (modificação estrutural). Os resultados demonstram que algumas formas desviantes que os aprendentes chineses produzem têm uma motivação percetiva (i.e. [w] para a lateral velarizada; [l] e [ɾə] para a vibrante alveolar), enquanto outras não podem ser analisadas como casos de perceção incorreta (como é o caso do o apagamento da vibrante em coda). Para além disso, na posição intervocálica, os aprendentes manifestam dificuldade na discriminação entre /l/ e /ɾ/ de forma bidirecional, mas, na produção, a lateral nunca é produzida incorretamente (/ɾ/ → [l], */l/ → [ɾ]). Tal revela uma divergência entre as duas modalidades de fala. Por contraste, mostrou-se que a ordem da aquisição (/ɾ/coda > /ɾ/ataque) é consistente na perceção e na produção da L2. A correspondência e a discrepância entre as duas modalidades de fala, sinalizam uma relação complexa entre a perceção e a produção na aquisição fonológica de L2. Em relação à questão da plasticidade das categorias de L2, recrutaram-se para as tarefas percetivas dois grupos de aprendentes nativos do mandarim que se diferenciavam substancialmente em termos da experiência em L2. Não se encontrou um efeito significativo da experiência da L2. A implicação deste resultado nulo no desenvolvimento fonológico de L2 foi discutida. O terceiro estudo desta tese tem como objetivo contribuir para a colmatação das lacunas entre estudos empíricos de L2 e as teorias formais. Adotando o Modelo Bidirecional de Fonologia e Fonética, formalizamos os resultados experimentais que as teorias atuais da aquisição fonológica de L2 não conseguem explicar, nomeadamente, a variação inter e intra-sujeitos na categorização fonológica em L2; a interação entre categorização fonológica e ortografia na construção das categorias na L2; a assimetria entre a perceção e a produção na L2. Em suma, esta tese contribui com dados empíricos para a discussão da relação complexa entre a perceção, produção e ortografia na aquisição fonológica de L2 e formaliza a interação entre essas modalidades através de um modelo linguístico generativo. Além disso, apresentam-se predições testáveis para investigação futura e sugestões para o aperfeiçoamento das metodologias de ensino/treino da língua não materna

Loan Phonology

For many different reasons, speakers borrow words from other languages to fill gaps in their own lexical inventory. The past ten years have been characterized by a great interest among phonologists in the issue of how the nativization of loanwords occurs. The general feeling is that loanword nativization provides a direct window for observing how acoustic cues are categorized in terms of the distinctive features relevant to the L1 phonological system as well as for studying L1 phonological processes in action and thus to the true synchronic phonology of L1. The collection of essays presented in this volume provides an overview of the complex issues phonologists face when investigating this phenomenon and, more generally, the ways in which unfamiliar sounds and sound sequences are adapted to converge with the native language’s sound pattern. This book is of interest to theoretical phonologists as well as to linguists interested in language contact phenomena