Some /l/s are darker than others: Accounting for variation in English /l/ with ultrasound tongue imaging

The phenomenon of /l/-darkening has been a subject of linguistic interest due to the remarkable amount of contextual variation it displays. Although it is generally stated that the light variant occurs in onsets (e.g. leap) and the dark variant in codas (e.g. peel), many studies report variation in different morphosyntactic environments. Beyond this variation in morphosyntactic conditioning, different dialects of English have been reported as showing highly variable distributions. These descriptions include a claimed lack of dis- tinction in the North of England, a three-way distinction between light, dark and vocalised /l/ in the South-East, and a gradient continuum of darkness in American English. This paper presents ultrasound tongue imaging data collected to test dialectal and contextual descriptions of /l/ in English, providing hitherto absent instrumental evidence for different distributions. Data from speakers of RP, Manchester, Essex and American English show that dialectal diversity has been vastly underestimated in the existing literature on /l/- darkening. The wide range of dialectal diversity, for which this paper provides only a small subset, shows a great deal of orderliness when paying due consideration to the diachronic evolution of variable phonological processes

/I/ velarisation as a continuum

In this paper, we present a production study to explore the controversial question about /l/ velarisation. Measurements of first (F1), second (F2) and third (F3) formant frequencies and the slope of F2 were analysed to clarify the /l/ velarisation behaviour in European Portuguese (EP). The acoustic data were collected from ten EP speakers, producing trisyllabic words with paroxytone stress pattern, with the liquid consonant at the middle of the word in onset, complex onset and coda positions. Results suggested that /l/ is produced on a continuum in EP. The consistently low F2 indicates that /l/ is velarised in all syllable positions, but variation especially in F1 and F3 revealed that /l/ could be “more velarised” or “less velarised” dependent on syllable positions and vowel contexts. These findings suggest that it is important to consider different acoustic measures to better understand /l/ velarisation in EP.</div

North American /l/ both darkens and lightens depending on morphological constituency and segmental context

It is uncontroversial that, in many varieties of English, the realization of /l/ varies depending on whether /l/ occurs word-initially or word-finally. The nature of this effect, however, remains controversial. Previous analyses alternately analyzed the variation as darkening or lightening, and alternately found evidence that the variation involves a categorical distinction between allophones or a gradient scale conditioned by phonetic factors. We argue that these diverging conclusions are a result of the numerous factors influencing /l/ darkness and differences between studies in terms of which factors are considered. By controlling for a range of factors, our study demonstrates a pattern of variability that has not been shown in previous work. We find evidence of morpheme-final darkening and morpheme-initial lightening when compared to a baseline of morpheme-internal /l/. We also find segmental effects such that, in segmental contexts which independently darken /l/, one can observe /l/ lightening, and contexts which independently lighten /l/ can make lightening effects undetectable. Morphological and prosodic effects are hence sometimes trumped by segmental context. Once contextual effects are controlled for, there is evidence both for morphologically-conditioned /l/-darkening and for morphologically-conditioned /l/-lightening, both of which can be understood as a result of prosodic differences reflecting morphological junctures

Foundations and Recent Trends in Multimodal Machine Learning: Principles, Challenges, and Open Questions

Multimodal machine learning is a vibrant multi-disciplinary research field that aims to design computer agents with intelligent capabilities such as understanding, reasoning, and learning through integrating multiple communicative modalities, including linguistic, acoustic, visual, tactile, and physiological messages. With the recent interest in video understanding, embodied autonomous agents, text-to-image generation, and multisensor fusion in application domains such as healthcare and robotics, multimodal machine learning has brought unique computational and theoretical challenges to the machine learning community given the heterogeneity of data sources and the interconnections often found between modalities. However, the breadth of progress in multimodal research has made it difficult to identify the common themes and open questions in the field. By synthesizing a broad range of application domains and theoretical frameworks from both historical and recent perspectives, this paper is designed to provide an overview of the computational and theoretical foundations of multimodal machine learning. We start by defining two key principles of modality heterogeneity and interconnections that have driven subsequent innovations, and propose a taxonomy of 6 core technical challenges: representation, alignment, reasoning, generation, transference, and quantification covering historical and recent trends. Recent technical achievements will be presented through the lens of this taxonomy, allowing researchers to understand the similarities and differences across new approaches. We end by motivating several open problems for future research as identified by our taxonomy

Sociophonetic variation in Stoke-on-Trent's pottery industry

This thesis presents a sociophonetic analysis of two dialect variables in twenty-six speakers from Stoke-on-Trent; specifically, speakers who worked in the city’s pottery industry. The recordings used come from an oral history archive, and much of the analysis presented considers the impact of the social and spatial structures of the pottery industry on dialect variation. The analysis presented also combines quantitative and qualitative methodologies in order to examine both broader patterns of dialect variation in the selected speakers, and how the same variables may be used in the construction of meaning-in-interaction. Finally, I consider the impact of using oral history data in this kind of sociophonetic analysis. I use literature on the social structures of the industry and the content of the recordings themselves to model an internal hierarchy for the industry, which I then examine alongside auditory and acoustic data from two linguistic variables: /h/-dropping, and the (i) vowel. /h/-dropping is particularly sensitive to industrial role, with speakers in mass production roles more likely to drop /h/ and those in administrative, managerial and design roles less likely to. I demonstrate how this links to the established social meanings of /h/-dropping as a historical dialect feature of English. The (i) vowel is less sensitive to this internal hierarchy quantitatively, but I describe how its realisation is particularly conditional on linguistic factors. Both variables are also examined qualitatively in discourse moments, and according to topic. /h/-dropping (and retention) appears to be associated with meaning on micro-, meso- and macro-social levels, allowing me to design an indexical field (Eckert, 2008) of its potential social meanings in this dataset. Variation in the (i) vowel appears to be less motivated by topic, but I demonstrate that some speakers do use more extreme acoustic tokens in particularly expressive talk

Caracterização acústica das consoantes líquidas do Português Europeu

Tese de doutoramento, Linguística (Diagnóstico e Intervenção), Universidade de Lisboa, Faculdade de Letras e Faculdade de Medicina, 2015O principal objectivo desta investigação é o de contribuir com dados empíricos para a caracterização acústica das consoantes líquidas do Português Europeu (PE). Apesar de este ser um tópico de estudo frequente em diversas línguas (Ladefoged & Maddieson, 1996; Recasens, 2012a), a generalidade dos trabalhos desenvolvidos para o PE incidem sobretudo sobre as líquidas laterais (Andrade, 1998, 1999; Marques, 2010; Monteiro, 2012; Oliveira, Martins, Teixeira, Maques, & Sá-Couto, 2011; Teixeira et al., 2012; entre outros), sendo que não são conhecidos estudos que contemplem os vários segmentos que integram a classe das líquidas (laterais e vibrantes). Foram gravadas e analisadas 2750 produções de 10 indivíduos adultos. Todos os participantes são falantes monolingues do PE, variante do sul do país, não apresentam historial de alterações de fala e/ou linguagem, nem de alterações auditivas. O conjunto de palavras reais utilizadas na recolha dos dados apresenta as seguintes características: palavras trissilábicas; padrão acentual paroxítono; as consoantes líquidas ocupam a sílaba média da palavra em ataque simples, ataque ramificado e coda e a vogal nuclear varia entre as sete vogais orais /i, e, ɛ, u, o, ɔ, a/. Os dados foram recolhidos no Laboratório de Audição e Terapia da Fala da Universidade do Algarve, numa cabine insonorizada, utilizando um microfone omnidireccional. O sinal acústico foi gravado a 16 bits e com uma frequência de amostragem de 44100 Hz, utilizando o software Audacity 2.0. A anotação do sinal acústico foi efetuada a partir da utilização do software Praat 5.3.30 (Boersma, 2001) e de acordo com métodos propostos por diversos autores. Todos os dados foram exportados para o SPSS 17.0, para a realização da análise estatística. Os resultados obtidos no presente estudo mostram, globalmente, que os segmentos pertencentes à classe das líquidas distinguem-se por intermédio de diversas propriedades acústicas, designadamente a frequência de F1, F2, F3, duração da líquida, duração da transição de F2 e declive da transição de F2, que sofrem influência, quer da posição silábica, quer do contexto vocálico adjacente, mas também das características individuais do falante. Quanto aos aspetos em comum, estes segmentos parecem partilhar, essencialmente, características no domínio espectral. As principais conclusões do estudo são as seguintes: i) Variabilidade de realizações fonéticas para os vários elementos constituintes da ii) segmentos com menor duração em ataque ramificado; iii) em coda, a lateral [l] apresenta valores de frequência de F1 significativamente mais elevados do que o observado para as demais posições silábicas; iv) para os valores de frequência de F2 de [l], não existem diferenças importantes entre posições silábicas perante vogais posteriores. Já para [ɹ], os valores de F2 são menores em ataque ramificado; v) quanto a F3, os valores de [l] são mais elevados em coda do que para as posições de ataque simples e ramificado. Os valores de [ɹ] são inferiores em ataque ramificado. A partir das conclusões apresentadas em iii), iv) e v), é reforçado o maior grau de velarização de [l] em coda. O declive da transição de F2 é também uma medida acústica importante para explicar o fenómeno de velarização da lateral alveolar /l/. São ainda apresentadas contribuições do estudo no âmbito do desenvolvimento típico e atípico dos sons da fala, designadamente a importância de considerar o contexto vocálico como uma variável clínica relevante. É também salientada a importância das características individuais do falante quer no processo de aquisição, quer no decurso do processo de intervenção terapêutica. classe das líquidas; ii) segmentos com menor duração em ataque ramificado; iii) em coda, a lateral [l] apresenta valores de frequência de F1 significativamente mais elevados do que o observado para as demais posições silábicas; iv) para os valores de frequência de F2 de [l], não existem diferenças importantes entre posições silábicas perante vogais posteriores. Já para [ɹ], os valores de F2 são menores em ataque ramificado; v) quanto a F3, os valores de [l] são mais elevados em coda do que para as posições de ataque simples e ramificado. Os valores de [ɹ] são inferiores em ataque ramificado. A partir das conclusões apresentadas em iii), iv) e v), é reforçado o maior grau de velarização de [l] em coda. O declive da transição de F2 é também uma medida acústica importante para explicar o fenómeno de velarização da lateral alveolar /l/. São ainda apresentadas contribuições do estudo no âmbito do desenvolvimento típico e atípico dos sons da fala, designadamente a importância de considerar o contexto vocálico como uma variável clínica relevante. É também salientada a importância das características individuais do falante quer no processo de aquisição, quer no decurso do processo de intervenção terapêutica.The main purpose of this study is to contribute to empirical data for the acoustic characterisation of European Portugues (EP) of liquid consonants. Althought this is a frequent topic of study in several languages (Ladefoged & Maddieson, 1996; Recasens, 2012a), the majority of the research done in EP has focused on lateral consoants (Andrade, 1998, 1999; Marques, 2010; Monteiro, 2012; Oliveira, Martins, Teixeira, Maques, & Sá- Couto, 2011; Teixeira et al., 2012; among others), and little is known about laterals and rhotics as a class. Data were collected from 10 adults. They were all monolingual speakers of European Portuguese, south variant, and none had history of speech and/or language disorders. The set of real words selected for data collection had the following characteristics: trissyllabic words; paroxytone stress pattern; the lateral /l/ occupied the middle word in onset; complex onset and coda positions; the nuclear vowel varied between seven oral vowels /i, e, ɛ, u, o, ɔ, a/. The speakers produced 2750 utterances. Data were recorded at the University of Algarve, in a sound proof booth, using a omnidirectional microphone. The acoustic signal was recorded at 16 bits and a sampling frequency of 44100 Hz, using Audacity 2.0. The annotation of the acoustic signal was performed using Praat 5.3.30 (Boersma, 2001) and according to methods proposed by several authors. All data were exported to SPSS 17.0, for statistical analysis. The results obtained in this study show that liquid consonants are distinguished by several acoustical properties, particularly the frequency F1, F2, F3, the durantion of liquid consonant, the duration of the slope of the F2 transition and the slope of the F2 transition, which are influenced by either the syllabic position or the adjacent vowel context and the individual characteristics of the speaker. The segments seem to share essentially spectral characteristics. The main conclusions of this research are the following: i) Liquid consonants demonstrate greater phonetic variability; ii) Liquid consoants are shorter in complex onset; iii) For [l], first formant (F1) frequency values are significantly higher in coda than in others syllabic positions; For [l], second formant (F2) frequency values are not important differences between syllabic positions in back vowel contexts. For [ɹ], F2 frequency values are lower in complex onset; v) For [l], third formant (F3) frequency values are higher in coda than in onset e complex onset positions. For [ɹ], F3 frequency values are lower in complex onset; From the conclusions presented in iii), iv) e v) the highest degree of velarisation of [l] in coda is reinforced. The slope of F2 transition is also an important measure for explaining the velarisation of alveolar lateral /l/. They are also presented contributions of the study for typical and atypical development of speech sounds, namely the importance of the vowel context in clinical practice. It also shows the importance of individual characteristics of speakers in the process of speech and language acquisition and during the clinical intervention process