On Nov 18, Ph.D. student Seung-Eun Kim successfully defended her dissertation thesis entitled:   "Experimental and computational investigations of F0 control."

Shown in the picture, from left - Seung-Eun Kim, committee member Dr. Draga Zec (attending remotely), committee member Dr. Abby Cohn, and Committee Chair Dr. Sam Tilsen. 

Abstract:

This dissertation examines speakers’ cognitive control of F0, by proposing and evaluating target-control and register-control hypotheses. In the target-control hypothesis, it is individual pitch targets that speakers control to produce variations in F0, whereas in the register-control hypothesis, it is the control of pitch register (in which the pitch targets are defined) that induces F0 variations. These alternative hypotheses are assessed through a production experiment and computational modeling.

The production experiment investigates speakers’ (i) pre-planned and (ii) adaptive F0 control. In particular, the experiment examines whether speakers vary F0 parameters (i) according to the initially planned sentence length and (ii) in response to the unanticipated changes in the length. For this purpose, a novel experimental paradigm was developed in which the stimuli cueing the parts of the utterance were delayed until after detection of utterance initiation; in this case, participants had to dynamically adapt to the changes in the length and content of the utterance. Analyses of F0 trajectories found strong evidence for both pre-planned and adaptive control. Further analyses were conducted to identify which specific F0 parameter was controlled (targets vs. register), and the results demonstrated the control of pitch register.

In the modeling study, a gestural model of F0 control was proposed and evaluated with the empirical data. The main feature of this dynamical model is that the normalized targets of F0 gestures (and F0 tract variable) are mapped to actual F0 values through pitch register parameters. The model parameters were optimized to minimize the difference between the empirical F0 contour and the model-generated contour. Several variants of F0 models were compared to examine the target vs. register-control hypotheses. The results found that the F0 model in which the register parameters varied (with invariant targets) outperformed the model in which the target parameters varied (with constant register), providing further support for the register-control hypothesis.

Overall, this dissertation provides evidence that for a given utterance, speakers have a set of invariant cognitive representation of high and low pitch targets, and they control pitch register to realize the abstract representation into different F0 peaks and valleys.

On Nov 14, Ph.D. student Sireemas Maspong successfully defended her dissertation thesis entitled:   "The relationship between register and vowel quality in Austroasiatic languages".   

Siri is shown here, from the left:  committee member Dr. Abigail Cohn, committee Co-Chair Dr. Sam Tilsen, Sireemas Maspong, committee chair Dr. John Whitman, committee member Dr. Michael Weiss.

Abstract:

This dissertation explores the status of voice quality as a cue to register contrast from diachronic and synchronic perspectives. Two main questions are investigated: (i) what is the source of vowel quality change in register languages? (ii) what is the cognitive representation of register? Is vowel quality associated with a separate gesture from other cues to register?

We explore these issues from a historical study and two acoustic studies of three Austroasiatic languages: Khmer, Eastern Khmu, and Chanthaburi Khmer.

This dissertation shows that vowel quality distinction can derive directly from the onset voicing contrast. Furthermore, we propose two possible gestural representations: (i) vowel quality and voice quality as cues to register are associated with a single gesture, or (ii) they are associated with separate gestures, but the two gestures are coordinated.

PhD Candidate Brynhildur Stefansdottir traveled to her native Iceland in August to perform field research for her dissertation on  the reduction of voiced fricatives in Icelandic speech.

During her visit she recorded 32 Icelandic speakers for an acoustic production study on the realization of intervocalic fricatives. 

During her three week stay she was lucky enough to get several days of sun.   stay. Special thanks to her old secondary school Laugalækjarskóli, for allowing her to record there, and to the teachers and employees for being such willing participants! 

Ph.D. candidate Nielson Hul had an extremely busy summer 2022. 

He presented his research on Khmer plosives at SEALS 2022 (Southeast Asian Linguistics Society), held at the University of Hawai'i at Manoa on May 18-20, 2022

Nielson also taught Khmer at SEASSI (Southeast Asian Studies Summer Institute), held at UW Madison from June 19 to August 11. 

And in between these activities, Nielson somehow found time to teach Khmer to a US government organization.