Effects of deafness on acoustic characteristics of American English tense/lax vowels in maternal speech to infants

Recent studies have demonstrated that mothers exaggerate phonetic properties of infant-directed (ID) speech. However, these studies focused on a single acoustic dimension (frequency), whereas speech sounds are composed of multiple acoustic cues. Moreover, little is known about how mothers adjust phonetic properties of speech to children with hearing loss. This study examined mothers’ production of frequency and duration cues to the American English tense/lax vowel contrast in speech to profoundly deaf (N = 14) and normal-hearing (N = 14) infants, and to an adult experimenter. First and second formant frequencies and vowel duration of tense (/i/, /u/) and lax (/I/, /ʊ/) vowels were measured. Results demonstrated that for both infant groups mothers hyperarticulated the acoustic vowelspace and increased vowel duration in ID speech relative to adult-directed speech. Mean F2 values were decreased for the /u/ vowel and increased for the /I/ vowel, and vowelduration was longer for the /i/, /u/, and /I/ vowels in ID speech. However, neither acoustic cue differed in speech to hearing-impaired or normal-hearing infants. These results suggest that both formant frequencies and vowel duration that differentiate American English tense/lx vowel contrasts are modified in ID speech regardless of the hearing status of the addressee

Dutch Word Stress as Pronounced by Indonesian Students

This study focuses on the way in which the Dutch monophthongal vowels are pronounced by Indonesian students. To investigate whether Indonesian students realize the Dutch vowels correctly, especially when they are stressed, I analysed duration and quality of stressed and unstressed Dutch vowels. Measurements were done on the duration and the formant frequencies of the vowels spoken by Indonesian students and by native speakers of Dutch as well. Statistical analysis showed that in general the differences in duration between vowels spoken by the Indonesian students and by the native speakers were not significant. However, the effect of stress on the lengthening of the vowels was stronger for the Indonesian students than for the native speakers. In addition, statistical analysis of the formant frequencies confirmed that the non-native speakers realized the Dutch vowels slightly differently from the Dutch native speakers. The Indonesian students pronounced the stressed vowels more clearly than their unstressed counterparts; yet their vowel diagram is smaller than the vowel diagram of the native speakers

Vowel Production in Mandarin Accented English and American English: Kinematic and Acoustic Data from the Marquette University Mandarin Accented English Corpus

Few electromagnetic articulography (EMA) datasets are publicly available, and none have focused systematically on non-native accented speech. We introduce a kinematic-acoustic database of speech from 40 (gender and dialect balanced) participants producing upper-Midwestern American English (AE) L1 or Mandarin Accented English (MAE) L2 (Beijing or Shanghai dialect base). The Marquette University EMA-MAE corpus will be released publicly to help advance research in areas such as pronunciation modeling, acoustic-articulatory inversion, L1-L2 comparisons, pronunciation error detection, and accent modification training. EMA data were collected at a 400 Hz sampling rate with synchronous audio using the NDI Wave System. Articulatory sensors were placed on the midsagittal lips, lower incisors, and tongue blade and dorsum, as well as on the lip corner and lateral tongue body. Sensors provide five degree-of-freedom measurements including three-dimensional sensor position and two-dimensional orientation (pitch and roll). In the current work we analyze kinematic and acoustic variability between L1 and L2 vowels. We address the hypothesis that MAE is characterized by larger differences in the articulation of back vowels than front vowels and smaller vowel spaces compared to AE. The current results provide a seminal comparison of the kinematics and acoustics of vowel production between MAE and AE speakers

Acoustic Characteristics of Tense and Lax Vowels Across Sentence Position in Clear Speech

The purpose of this study was to examine the acoustic characteristics of tense and lax vowels across sentence positions in clear speech. Recordings were made of 12 participants reading monosyllabic target words at varying positions within semantically meaningful sentences. Acoustic analysis was completed to determine the effects of Style (clear vs. conversational), Tenseness (tense vs. lax), and Position (sentence-medial vs. sentence-final) on vowel duration, vowel space area, vowel space dispersion, and vowel peripheralization. The results showed speakers had longer durations and expanded vowel spaces in clear speech for both tense and lax vowels. Importantly, the amount of increase was similar for tense and lax vowels suggesting the defining properties of lax vowels (i.e., short duration and centralization) were manipulated in clear speech. A significant main effect of position for lax vowel space expansion showed greater vowel spaces for lax vowels in sentence-medial position in clear speech. Clear speech vowel adaptations appear to be dynamic with both vowel-specific and general transformations

Perception of German and Danish vowels with special reference to the German lax vowels /I, Y, U/

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English orthographic forms affect L2 English speech production in native users of a non-alphabetic writing system

There is growing evidence that the orthographic forms (spellings) of second language words affect second language (L2) speech production, but it is not known whether orthography affects L2 phonology in native users of a non-alphabetic writing system. To answer this question, this study tested the effects of number of letters on the duration of consonants and vowels in the EnglishL2 speech production of Japanese-English sequential bilinguals. JapaneseL1-EnglishL2 bilinguals and English native speakers (both n = 16) performed a delayed word repetition task, producing 16 English word pairs in which the same consonant or vowel was spelled either with a single letter or with double letters, as in city-kitty. The bilinguals produced the same English sound as longer or shorter depending on the number of letters in its spelling, confirming that L2 orthographic forms affect L2 speakers’ phonological representations of L2 words even when their L1 writing system is not alphabetical

The local intelligibility of brazilian learners’ speech in english (l2) to argentinian and german listeners : a discussion on non-native perception from a complex, dynamic perspective

This thesis aims to investigate the intelligibility of the L2 English spoken by Brazilian learners when perceived by other non-native learners. We examine the local intelligibility (MUNRO; DEWING, 2015) of words with the vowels [æ] – [ɛ] and [i] – [ɪ]. We adopt a Complex, Dynamic view of language (DE BOT; LOWIE; THORNE, 2013, BECKNER et al., 2009; LARSEN-FREEMAN, 2017) and apply two complementary analyses, inferential and exploratory, in order to observe (a) the intelligibility rates of the target words produced by our participants; (b) the variables that have effects on the identification of the target vowels; and (c) the acoustic and participant-related characteristics that play a role in that identification. We collected samples produced by six Brazilian learners of English, at three levels of proficiency, all native speakers of Porto-Alegrense Brazilian Portuguese. Additionally, two native speakers of Canadian English provided baseline tokens. We selected 128 sentences as stimuli for the forced-choice perception task. Our 46 listeners were organised in two groups: Argentinian native speakers of Riverplate Spanish, and German native speakers of Central German. As for our first goal, our mixed-effects logistic models show an effect of the listener’s L1 on the intelligibility rates of the words with the [æ] – [ɛ] vowels. Tokens with [æ] were more intelligible to Germans, and the ones with [ɛ] were more intelligible to Argentinians. L1 was not significant for the accurate identification of words with [ɪ], but it was for tokens with [i]; Germans showed higher accuracy rates than Argentinians. As for our second goal, our model calculated L1 as a significant predictor variable of vowel identification for the mid/low pair, but not for the tense/lax one. F1 was not a significant predictor for the identification of [æ] and [ɛ], but it was for [i] and [ɪ]. F2 was significant for both pairs. The inferential statistics was complemented by an exploratory analysis, which took into account those statistically significant variables, as well as speakers’ proficiency levels and the length of the vowels in the stimuli. As for our third goal, our stimulus-by-stimulus analyses suggest that participant-related characteristics and acoustic cues are combined by the listeners in different ways, leading to emerging phenomena. We found that the temporal cue seems to play a strong role in the perception of the four vowels by Germans, a role that is not so clear in the perception of [ɛ] or [i] by Argentinians. Our exploratory investigation also suggests that both groups of listeners take the temporal cue in combination with F1 and F2, though the decisive status of those spectral cues appears more clearly in Argentinian identifications. Overall, our analyses suggest that the hybrid nature of both the non-native speakers’ and listeners’ systems will lead to emerging phenomena, as a result of the Complex, Dynamic way in which individual systems have developed. We understand that our findings highlight the need to take both speaker and listener into account when investigating L2 speech intelligibility, thus confirming the dynamic and complex nature of this process.O presente trabalho investiga a inteligibilidade do inglês (L2) falado por aprendizes brasileiros quando percebido por outros aprendizes não-nativos. Avalia-se a inteligibilidade local (MUNRO; DEWING, 2015) de palavras com as vogais [æ] – [ɛ] e [i] – [ɪ]. O trabalho adota uma visão de língua como Sistema Dinâmico e Complexo (DE BOT et al., 2013, BECKNER et al., 2009; LARSEN-FREEMAN, 2017) e utiliza-se de métodos complementares de análise, inferenciais e exploratórios, para investigar (a) a inteligibilidade das palavras-alvo produzidas pelos falantes no presente estudo; (b) as variáveis que têm efeitos sobre a identificação das vogais-alvo; e (c) o papel de características acústicas e relacionadas aos participantes nessa identificação. Foram coletadas produções de seis brasileiros aprendizes de inglês, em três níveis de proficiência, nativos da variedade porto-alegrense de português brasileiro. Dois falantes nativos de inglês canadense forneceram tokens de controle. Foram selecionados 128 estímulos para a tarefa de percepção de escolha forçada. Os 46 ouvintes compunham dois grupos: argentinos nativos de espanhol rio-platense, e alemães nativos de alemão central. Em relação ao primeiro objetivo da presente dissertação, os modelos logísticos de efeitos mistos mostraram efeito da L1 do ouvinte na inteligibilidade de palavras com as vogais [æ] – [ɛ]. Palavras com [æ] foram mais inteligíveis para alemães, e aquelas com [ɛ], para argentinos. A L1 não foi significativa para a identificação correta de palavras com [ɪ], mas o foi para palavras com [i]; alemães tiveram maior acuidade do que argentinos. Em relação ao segundo objetivo, o modelo apontou que L1 constitui variável preditora significativa na identificação de vogais do par médio/baixo, mas não do tenso/frouxo. A variável F1 não foi significativa para a identificação de [æ] e [ɛ], mas o foi para a de [i] e [ɪ]. F2 foi significativa para ambos os pares. A análise estatística foi complementada pela exploratória. Esta última considerou as variáveis estatisticamente significativas, bem como o nível de proficiência dos falantes e a duração das vogais nos estímulos. A análise estatística foi complementada, em relação ao terceiro objetivo, com a análise estímulo-por-estímulo, que sugere que tanto características relacionadas aos participantes quanto pistas acústicas são combinadas de diferentes maneiras pelos ouvintes, levando a fenômenos emergentes. Os resultados indicam que a pista temporal tem um papel forte na percepção das quatro vogais do inglês pelos alemães, papel esse menos claro na percepção de [ɛ] or [i] pelos argentinos. A análise exploratória sugere, ainda, que ambos os grupos de ouvintes tomaram a pista temporal em conjunto com F1 e F2, embora o status decisivo dessas pistas espectrais pareça mais claro nas identificações por argentinos. De modo geral, os resultados do presente trabalho sugerem que a natureza híbrida dos sistemas dos falantes e dos ouvintes não nativos permitiram a emergência de fenômenos, em função da maneira dinâmica e complexa com que cada sistema individual se desenvolve. Entende-se que os resultados apresentados evidenciam a necessidade de considerar tanto ouvinte quanto falante em investigações acerca da inteligibilidade da fala em L2, confirmando, assim, a natureza dinâmica e complexa desse processo

Acoustic Characteristics of Vowels Produced by Young Children from the New Orleans Area

Understanding dialects and their effects on speech and language is integral to the field of speech-language pathology, as dialectal differences could potentially be misdiagnosed as speech or language disorders if these factors are not well-considered. The number and organization of the vowel system of one regional dialect of American English differs from those of another regional dialects. Therefore, understanding the effect of dialect on vowel productions in children can aid in the accurate evaluation of children from various dialectal backgrounds. The aims of the proposed study were to 1) determine the age at which young children develop acoustic markers of a given dialect and (2) provide the context in which the dialectal features are more prominent. Four three-year-olds whose parents lived in New Orleans, Louisiana, throughout their lives were included in the study. Target stimuli included 5 words for each of following vowels, /i, ɪ, ʊ, u, æ/. A single-word elicitation task and two sentence imitation tasks, one spoken by a speaker from New Orleans and the other from Iowa were used to elicit target sounds. Acoustic patterns of vowels produced by child participants were analyzed using vowel midpoint measured F1 and F2 and vowel duration. The results showed that not all children showed aspects of their dialectal patterns by age three and elicitation method had no considerable effect on vowel patterns of these children. These findings indicate that phonetic level refinement of vowels continue past the age of three and children’s vowel production is not affected by the context (imitative or spontaneous) in which the vowels are elicited

Combining research methods for an experimental study of West Central Bavarian vowels in adults and children

The overall goal of this thesis was to systematically measure defining vowel characteristics of the West Central Bavarian (WCB) dialect for an acoustically based analysis of the Bavarian vowel system and simultaneously investigate to what extent these characteristics are being preserved across generations and if there is a sound change in progress observable in which young speakers show more characteristics of Standard German (SG) than old on some Bavarian vowel attributes. In order to address these aims we conducted acoustic recordings of WCB speaking adults and WCB speaking primary school children which were then compared to each other with an apparent-time analysis. For a more accurate view of changes in progress we combined this apparent-time comparison with longitudinal data from the WCB children, obtained at annually intervals expanding over three years. The acoustic data was enhanced by articulatory data gained from ultrasound recordings of a subset of the same WCB speaking children at two timepoints with one year interval. Analyses of the acoustic data revealed both adult/child and longitudinal changes in the direction of the standard in the children’s tendency towards a merger of two open vowels and a collapse of a long/short consonant contrast, neither of which exist in SG. There was some evidence that children in comparison with adults were beginning to develop both tensity and rounding contrasts which occur in SG but not WCB. There were no observed changes to the pattern of opening and closing diphthongs which differ markedly between the two varieties. Also, within the WCB front vowel that resulted historically from /l/-vocalization and for which articulatory data from a subset of the children was put into relation with the acoustic measures no changes were observed. The general conclusion is that WCB change is most likely to occur as a consequence of exaggerating phonetic variation that already happens to be in the direction of the standard and therefore internal factors motivated by general principles of vowel change might play a more decisive role in inducing a shift than external factors like dialect contact