The complex four-way voicing and aspiration contrast of Indic languages like Bengali is poorly understood, both in terms of their phonetic and phonological properties. Voice Onset Time (VOT) which is typically used to characterize voicing contrasts is not sufficient to distinguish the four laryngeal categories of languages like Bengali. Moreover, it is unclear how this contrast is represented in terms of phonological features. In this series of projects, I characterize the acoustic properties of connected Bengali speech in two different registers – Infant Directed Speech (IDS) and Adult Directed Speech (ADS). I consider what these acoustic properties suggest about how this complex contrast is represented phonologically and the phonetic dimensions along which voicing contrasts are organized in the world’s languages.

• Reconceptualizing VOT: Further Contributions to Marking 50 Years of Research on Voice Onset Time, paper under review at Journal of Phonetics
  I argue that VOT should be reconceptualized as a two-dimensional plane rather than a one-dimensional continuum. This simple reformulation of VOT under which negative and positive VOT make up the complete VOT space yields a more complete description of the voicing contrasts that exist in the world’s languages.
• Acoustic Properties of the Four-Way Laryngeal Contrast in Bengali Infant Directed Speech, ICPhS 2023 proceedings paper
  This paper analyzes the acoustic properties of the four-way laryngeal contrast in Infant Directed Speech (IDS). I show that this contrast is not globally hyper-articulated in Bengali IDS, as suggested by some studies on other languages, nor is Bengali IDS breathier than ADS.

• The four-way laryngeal contrast in Bengali IDS and beyond, ICPhS 2023 poster
  This poster describes the acoustic properties of the four-way laryngeal contrast and shows that splitting VOT into its positive and negative components adequately captures this contrast. This conception of VOT also better captures the typology of languages that contrast three laryngeal categories.

• Laryngeal realist representations in Bengali, MFM 2023 poster
  This poster argues that the four-way contrast is best represented by the phonological features [voice] and [spread] in line with theories of Laryngeal Realism, based on acoustic data from Bengali connected speech.

Infant Directed Speech (IDS) has been shown to be hyper-articulated and is thought to facilitate phonetic acquisition. This is particularly true for vowels and studies on consonant hyper-articulation have returned mixed results. This series of projects evaluate whether consonants and vowels IDS are, in fact, hyper-articulated and how phonetic categories may be learned from naturalistic data.

• Bootstrapping prosodic primitives from Infant Directed Speech, in-prep, to be submitted to the Journal of the Acoustical Society of America (with Megha Sundara)
  We show that language-specific prosodic categories can be learned solely from intensity and frequency information in the target language. We show that a clustering algorithm can find three clusters in Spanish and Bengali, two languages that differ in their intonational phonologies, and that, crucially, these learned clusters map onto prosodic groups that approximate the target intonational phonologies. This suggests that a learner that pays attention to the same set of acoustic cues will discover typologically appropriate functional categories that signal the prosodic structure of their target language.
• Evaluating the learnability of vowel categories from Infant-Directed Speech, Poster at the Meeting of the Acoustical Society of America, 2022 (with Katya Khlystova, Connor Mayer, Ann Aly, Ji Young Kim and Megha Sundara)
  In this poster we test the facilitative effect of IDS by evaluating the acoustic separability of English and Spanish vowels and independently testing the learnability of vowel categories using a previously implemented Gaussian learner (Feldman et al., 2013). We find some evidence for greater separation in in both English and Spanish IDS. However, the Bayesian distributional learner is unable to learn appropriate vowel categories consistently. Overall, we find no evidence for the facilitative effect despite greater vowel separability. We also find that the learner, which was previously validated on lab-speech, is unable to handle the variation found in naturalistic speech.

• The Four-way Voicing Distinction in Bengali Infant Directed Speech, Poster at the Meeting of the Acoustical Society of America, 2022 (with Megha Sundara)
  We show that stops and vowels in Bengali IDS are not hyper-articulated, nor are they more acoustically separable. Some stops are, in fact, hypo-articulated, but not as a result of enhanced vowel contrasts. Apparent hyper-articulation of stops is an effect of the slower speech rate of IDS. This suggests that IDS may not always facilitate phonetic learning.

Indic languages are reported to have a loanword adaptation pattern whereby English aspirated stops are adapted as unaspirated, even though Indic languages have phonological aspirates. This pattern is also observed in Indian varieties of English. This project describes and contrasts the acoustic properties of stops in Indian English and Southern British English, and explores the possibility of this adaptation pattern in loans and in Indian English having a perceptual explanation.

• An acoustic study of voiceless stops in Indian English, paper in the Journal of South Asian Linguistics, 2022 (with Peter Staroverov)

• The Curious Absence of Aspiration in Indian English: The Role of Phonetics in Adaptation, WCCFL 37 proceedings paper, 2021

In this ongoing collaboration with Ben Eischens, we are analyzing the acoustic properties of non-modal phonation in San Martín Peras Mixtec. Many Otomanguean languages contrast modal and laryngealized phonation, which is realized as a modal vowel followed by laryngealization. Previous work has shown that the production of laryngealization in other Mixtec varieties varies greatly both within and across speakers (Gerfen and Baker, 2005; Cortés et al., 2023). Preliminary results from our acoustic study show that laryngealized and breathy vowels in San Martín Peras Mixtec are realized remarkably consistently within and across speakers via durational cues.

In this collaborative project led by Gaby Hermon and the late Peter Cole, we documented Adonara (iso: adr), an Austronesian language spoken in eastern Indonesia. This collaboration included native speaker undergraduate students and Indonesian linguists. Audio and some video recordings are available on PARADISEC with transcription, glosses and English and Indonesian translations.