Grad Student Seung-Eun Kim presented a paper titled:  "The effects of speech rate on the phonetic correlates of syntactic structure" at the 95th Annual Meeting of the Linguistic Society of America (LSA 2022), held Jan 6-9, 2021.

Here is the abstract for her paper:

This study provides empirical evidence that speakers make prosodic contrasts to mark different syntactic structures.

This finding is obtained by examining articulatory and acoustic measures at prosodic boundaries in two types of English relative clauses, non-restrictive relative clauses (NRRC) and restrictive relative clauses (RRC).

Crucially, in examining their difference, the present study uses a moving visual analogue and elicits continuous variation in speech rate.

With this method, the study additionally shows that the prosodic contrasts which cue differences in syntactic structure are neutralized at fast speech rates.

Seung-Eun Kim presented a paper titled "The effects of speech rate on the phonetic correlates of syntactic structure" at the 95th Annual Meeting of the Linguistic Society of America, held Jan 7-10, 2021

Seung-Eun provided empirical evidence that speakers make prosodic contrasts to mark different syntactic structures, but these contrasts are neutralized at fast speech rates. Her  findings were obtained by examining articulatory and acoustic measures at prosodic boundaries in two types of English relative clauses.

Seung-Eun Kim presented a paper titled "The effects of speech rate on the phonetic correlates of syntactic structure" at the 95th Annual Meeting of the Linguistic Society of America, held virtually Jan 7-10, 2021.

Paper Abstract:

This study provides empirical evidence that speakers make prosodic contrasts to mark different syntactic structures, but these contrasts are neutralized at fast speech rates. T

These findings were obtained by examining articulatory and acoustic measures at prosodic boundaries in two types of English relative clauses. Non-restrictive relative clauses (NRRC) and restrictive relative clauses (RRC) are syntactically and semantically distinct. As in example (1), a NRRC is similar to a parenthetical, while a RRC crucially contributes to the meaning of the sentence. Given these differences, it is reasonable to predict that the two structures have different prosodic organization; in particular, Selkirk (2005) predicted the prosodic structure of the two clauses as in (1).

The present study thus examines whether the two structures are phonetically distinct. Moreover, in investigating their difference, the present study elicits continuous variation in speech rate and examines how the phonetic measurements associated with the two RCs vary by rate. While previous studies on speech rate and prosodic structure (e.g., Fougeron & Jun 1998) varied speech rate categorically, using instructions such as “speak fast or slow”, the current study uses a moving visual analogue to elicit continuous speech rate and examines how the speech rate affects prosodic variation.

Two hypotheses are examined: (a) boundary position differences: prosodic boundaries before (B1) vs. after (B2) the RC are different in each sentence, (b) syntactic differences: prosodic boundaries in NRRC vs. RRC are different at B1 and B2.

The results show strong evidence of boundary position differences, but mixed evidence for syntactic differences. In addition, the study found that the prosodic difference between the two structures is affected by speech rate.

Dan Cameron Burgdorf and Dr. Sam Tilsen presented a paper titled "Glides Prioritize Articulation, Vowels Prioritize Acoustics" at  the 95th Annual Meeting of the Linguistic Society of America (LSA 2021), held virtually Jan 7-10, 2021

Paper Abstract:

Little phonetic research has been done on the articulatory and acoustic differences between glides and vowels. These segments have been characterized in numerous ways phonologically, most commonly in terms of intrinsic differences of features or structural differences of syllable position, with respective predictions of phonetic differences in constriction or timing effects.

Articulatory and acoustic data from multiple experiments show that glides and vowels differ in another way entirely: glides are realized with greater articulatory precision than vowels, while vowels are realized with greater acoustic precision and greater sensitivity to acoustic feedback.

Experiment 1 collected articulatory (EMA) data and acoustic data from six native English speakers in an imitation task. Stimuli varied in duration and intensity from vowel-like to glide-like, for both [i]-[j] and [u]-[w]. The experiment was designed to test hypotheses concerning constriction, timing effects, and categoricity, but post hoc analysis of participants’ variances in measured parameters showed that spatial parameters, such as trajectory curvature and movement range, had more variance (less precision) for more vowel-like productions.

In contrast, acoustic parameters, formants and their transitions, had more variance (less precision) for more glide-like productions. Some parameters found to have substantial variance responses across the stimulus space had little or no response in the parameter itself, indicating that greater or lesser precision was not necessarily contingent on any shift in mean value.

Experiments 2 and 3 expanded on this finding with the use of an altered feedback paradigm (AFP). AFPs are studies in which the participant hears a real-time playback of their voice which is, unknown to them, altered in some fashion. This alteration elicits compensation, in which participants change their production so that the feedback they hear better resembles their intended target. AFPs have been applied to vowels previously (e.g. Houde 2011) by altering the formants of the (usually mid front) vowel to be perceived as a different vowel (e.g., [ɛ] to [i] or [æ]). The use of an AFP on high vowels and glides allowed for testing of the hypothesis that glides prioritize other forms of feedback (e.g. somatosensory) over acoustic feedback and would therefore show less compensation than vowels.

Experiment 2 presented 21 native English speakers with auditory models of /biə/ ‹bia› and /bjə/ ‹bya› and subsequently cued participants orthographically. Feedback alteration was achieved with Audapter, a software package for real-time manipulation of acoustic parameters of speech. Maximum alteration was an increase of F2 by 250Hz and a decrease of F1 by 120Hz, effectively making the input sound more high and more front. Alteration tapered off within each word to avoid altering the formants of the final vowel.

Experiment 3 (underway) applied a similar alteration to /duə/ ‹dua› and /dwə/ ‹dwa›. Some participants responded unexpectedly by lengthening their vowels to outlast the period of alteration. Of participants whose vowels were short enough to be fully altered as intended, most showed substantially more compensation for vowels than for glides, as predicted.

Additionally, the acoustic findings from Experiment 1 were replicated: both during baseline periods with no alteration and while alteration was applied, most participants had greater variance in their formants for glides than for vowels. These findings point to a kind of difference between glides and vowels that, despite being unpredicted by standard phonological approaches, is not unintuitive if the category of glides is generalized to consonants.

Glides, as consonants, prioritize the articulatory domain, where they’re realized with a degree of consistency regardless of acoustic results. Vowels prioritize the acoustic domain, and more readily adjust their articulation to meet acoustic targets.

This difference may underlie broad patterns in the phonological and phonetic behavior of consonants and vowels.