Sireemas Maspong & Francesco Burroni presented a poster titled: "Functional Load modulates speech production, but not speech perception: Evidence from Thai vowel length"  at the 12th International Seminar on Speech Production (ISSP), virtually held Dec 14-18, 2020

Poster Abstract: 

The functional load (FL) of a phonological contrast has been shown to correlate with its resistance to merger on evolutionary timescales. The effects of FL on day-to-day speech, however, remain an uncharted territory.

In this paper, we studied the effects of FL in a production and in a perception study of vowel length contrasts in Bangkok Thai. We found that, in production, FL had a positive correlation with long/short vowel duration ratios, as well as with the discriminability between short and long vowels distributions. In perception, we found no correlations between FL and logistic function slope of the responses or between FL and reaction times.

Elaborating on the asymmetric effects of FL on production and perception, we hypothesize that different units and mechanisms involved in each process, as well as their relationship to phonological contrast, are responsible for the asymmetry. Moreover, we discuss the implications of our findings for theories of sound change that privilege perception over production. Finally, we conclude by discussing how the real time effects of FL on vowel length contrasts production may be accommodated in a nonlinear dynamical model of phonological contrast.

Seung-Eun Kim and Dr. Sam Tilsen present poster titled "Temporal localization of syntactically conditioned prosodic information" at the 12th International Seminar on Speech Production (ISSP 2020), held virtually on Dec 14-18, 2020.

Poster Abstract:

This study investigates when in time the prosodic correlates of a syntactic contrast can be detected in acoustic and articulatory signals.

Specifically, we attempt to localize information that distinguishes non-restrictive relative clauses (NRRCs) and restrictive relative clauses (RRCs), examples of which are shown in (1). On several accounts (e.g., Selkirk 2005), the two types of relative clauses differ in prosodic phrase structure, and this predicts that the utterances in (1) should differ in the vicinity of the phrase boundaries before (B1) and after (B2) the relative clause. To test this prediction, we used a neural network-based analysis procedure.

The results showed that for some speakers, the syntactically conditioned prosodic information was distributed in a wide region around prosodic boundaries, while for the other speakers, the information was more concentrated at specific locations. For those speakers who showed concentrated patterns, there was variation in where prosodic information was located relative to phrase boundaries.

Dan Cameron Burgdorf and Dr. Sam Tilsen presented a poster titled "Compensation for Altered Feedback in Vowels and Glides" at the 12th International Seminar on Speech Production (ISSP 2020), held virtually Dec 14-18, 2020

Poster Abstract:

This study uses altered feedback to investigate whether there is difference between vowels and glides in the priority of auditory feedback.

It was hypothesized that auditory feedback is more important in the production of vowels than glides, and thus compensatory responses to feedback perturbation were predicted to be larger for vowels than for glides. Participants were cued to repeat the nonce words /biʌ/ and /bjʌ/, and their productions were altered to increase F2 by 250Hz and decrease F1 by 120Hz, effectively making the target sounds more high and more front.. The alteration was limited to a 100ms period beginning from the acoustic release of /b/.

Whether participants exhibited the hypothesized asymmetry in compensatory response depended on their vowel durations. Participants who produced shorter /i/ vowels compensated more for the vowel than the glide, as expected. Participants who produced longer /i/ vowels generally showed less compensation for the vowel than for the glide, likely because the alteration was only applied during part of their vowels.

Seung-Eun Kim and Dr. Sam Tilsen presented a poster titled "Phonetic evidence for categorical differences in prosodic structure" at the 179th Meeting of the Acoustical Society of America, held virtually Dec 7-11, 2020

Poster Abstract:

An experiment was conducted to assess phonetic evidence for categorically distinct prosodic structures associated with two types of relative clauses in English. Non-restrictive relative clauses (NRRCs) and restrictive relative clauses (RRCs) have been argued to be typically produced with different prosodic phrase structures.

To test whether there is evidence for this, productions of the two relative clauses were elicited. A wide range of variation in speech rate was elicited by using a moving visual analogue which cued participants for rate variation. Acoustic and articulatory data were collected from twelve participants.

We assessed whether the functional relations between speech rate and various phonetic measures at phrase boundaries differed by syntactic context. In addition, linear and sigmoidal models were fit to each of the articulatory and acoustic measures within each syntactic context, and the corrected Akaike Information Criterion (AICc) was used to determine whether the sigmoidal model provides a substantially better fit than the linear model.

Although most of the phonetic measures showed a significant difference between the two syntactic structures, which provides some evidence for distinct prosodic categories, the non-linearity analyses in both structures showed weak evidence for categorical variation in prosodic structure.