This is my first professional (as opposed to personal) youtube video, on my work channel for Maps of Speech. Today I’m making my debut with a scientific report on colorized schlieren images of speech air flow with and without masks. Please share widely, and encourage others to share widely. This is intended to be a worldwide release, and has been approved by the New Zealand Ministry of Business, Innovation, and Employment’s communications team, as well as our COVID-research team. In general, videos on this channel are more formal than my HoT videos, and will often be made in collaboration with whatever research team is working on the related projects. The details below this video link to three other unlisted videos that show the entirety of the schlieren videos referenced – without any audio commentary.
Wayland Joseph Blue, myself, and Carrien Leith Blue have co-authored a paper on the benefits of community-based health education and nutritional support on the birth outcomes among migrant workers in Maesot, Thailand, recently published in the International Social Science Review.
We worked on this article together because it was important to share with the world how low-cost education and nutritional supplementation can massively improve birth weight and early childhood health. The Charis Project / Shade tree Foundation have been active on such tasks for many years now, and I have be honoured to get to be a part of documenting their great work. To quote the first author Wayland: “These approaches aren’t limited to developing countries. They are as relevant in inner-city communities in the United States as they are in rural Thailand and Myanmar.”
The acknowledgment section of the article didn’t make it through proofing, so I put that material here on my website. We wanted to thank Zohreh Bayatrizi for being an early reader of the article and providing great feedback, and for TinTin’s efforts in helping us meticulously work through all of the data we had – she spend many days enduring my rather thorough questions. These questions extended beyond what we put in the article, and helped Charis reorganize their records. I am also grateful that UC permitted me to spend some of my Sabbatical time on this task as it is outside of my usual research focus. In addition, Pi Gamma Mu has proven itself dedicated to making excellent social science research freely available. In an age of far too many important articles behind paywalls, I am glad that this article is not, and I would like to thank Pi Gamma Mu and all of their alumni for making this possible.
Here is presented a retrospective review of the Charis Project’s Family Engagement Program (FEN) as it existed in 2014-2017. FEN was a program of women’s health education, nutrition supplements, and family visitation. The education program consisted of a 12-week course on nutrition, maternity, and sex education taught individually and in groups, focusing on pregnant Burmese migrant laborers, but including approximately 20 percent male participation. The nutrition supplements consisted of 5 kilograms of fresh vegetables and 12 eggs weekly to pregnant mothers, from course onset to about six months after childbirth depending on family needs. Family visitation took place during food deliveries, and focused on individual counselling and family stability. The program served 39 families from 2014-2017. FEN did not reduce neonatal mortality (due to a miscarriage and severe congenital birth defect), but resulted in all surviving infants being born normal weight and surviving to the end of 2019, representing a significant improvement over the 25.6 percent low birth weights reported for Kayin State, Myanmar.
Jason A. Shaw, Christopher Carignan, Tonya Agostini, Robert Mailhammer, Mark Harvey and I have recently had an article on Iwaidja accepted to Language. The article is now out, is an open publication, and can be accessed at project MUSE here.
It was a privilege to be a part of this project!. The article represents several years of work on the part of all of us – my part seeming to me to be the least of all. We acknowledge a host of granting agencies, lab supporters, and researchers, but most of all the Iwaidja speakers: Charlie Mangulda, David Cooper, James Cooper, Henry Guwiyul, Ilijili Lamilami, Isobel Lamilami, and Maggi Maburnbi for sharing the Iwaidja language and culture. (For those of you who don’t know, Iwaidja is an endangered Australian Language from NorthWest Australia.) The abstract itself summarizes the article succinctly.
A field-based ultrasound and acoustic study of Iwaidja, an endangered Australian aboriginal language, investigated the phonetic identity of non-nasal velar consonants in intervocalic position, where past work had proposed a [+continuant] vs [-continuant] phonemic contrast. We analyzed the putative contrast within a continuous phonetic space, defined by both acoustic and articulatory parameters, and found gradient variation from more consonantal realizations, e.g. [ɰ], to more vocalic realizations, e.g. [a]. The distribution of realizations across lexical items and speakers did not support the proposed phonemic contrast. This case illustrates how lenition that is both phonetically gradient and variable across speakers and words can give the illusion of a contextually restricted phonemic contrast.
Matthias Heyne, Xuan Wang, myself (Donald Derrick), Kieran Dorreen, and Kevin Watson have recently had an article documenting the articulation of /ɹ/ in New Zealand English.
This work is therefore in part a follow-up to some of my co-authored research into biomechanical modelling of English /ɹ/ variants, indicating that vocalic context influences variation through muscle stress, strain, and displacement. It is, by these three measures, “easier” to move from an /i/ to a tip-down /ɹ/ , but from /a/ to a tip-up /ɹ/.
In this study, for speakers who vary at all (some only do tip-up or tip-down), they are most likely to produce tip-up /ɹ/ in these conditions:
back vowel > low central vowel > high front vowel
initial /ɹ/ > intervocalic /ɹ/ > following a coronal (“dr”) > following a velar (“cr”)
The results show that allophonic variation of NZE /ɹ/ is similar to that in American English, indicating that the variation is caused by similar constraints. The results support theories of locally optimized modular speech motor control, and a mechanical model of rhotic variation.
The abstract is repeated below, with links to articles contained within:
This paper investigates the articulation of approximant /ɹ/ in New Zealand English (NZE), and tests whether the patterns documented for rhotic varieties of English hold in a non- rhotic dialect. Midsagittal ultrasound data for 62 speakers producing 13 tokens of /ɹ/ in various phonetic environments were categorized according to the taxonomy by Delattre & Freeman (1968), and semi-automatically traced and quantified using the AAA software (Articulate Instruments Ltd. 2012) and a Modified Curvature Index (MCI; Dawson, Tiede & Whalen 2016). Twenty-five NZE speakers produced tip-down /ɹ/ exclusively, 12 tip-up /ɹ/ exclusively, and 25 produced both, partially depending on context. Those speakers who produced both variants used the most tip-down /ɹ/ in front vowel contexts, the most tip- up /ɹ/ in back vowel contexts, and varying rates in low central vowel contexts. The NZE speakers produced tip-up /ɹ/ most often in word-initial position, followed by intervocalic, then coronal, and least often in velar contexts. The results indicate that the allophonic variation patterns of /ɹ/ in NZE are similar to those of American English (Mielke, Baker & Archangeli 2010, 2016). We show that MCI values can be used to facilitate /ɹ/ gesture classification; linear mixed-effects models fit on the MCI values of manually categorized tongue contours show significant differences between all but two of Delattre & Freeman’s (1968) tongue types. Overall, the results support theories of modular speech motor control with articulation strategies evolving from local rather than global optimization processes, and a mechanical model of rhotic variation (see Stavness et al. 2012).
My name is Donald Derrick, and this web-site is dedicated to presenting my research on speech production and perception.
On the production side, I examine vocal tract motion (both shape and muscle position), air flow, oral and nasal acoustics, and visual face motion. I then use this production information to study audio, visual, and tactile speech perception. The purpose is to identify constraints on low level production, and low level percepts that can enhance or interfere with speech perception.
This research has helped identify constraints such as gravity, muscle elasticity, and end-state-comfort on speech production and brought in true multi-modal speech perception research by adding (aero)-tactile speech into audio-visual speech study. I have used this research to expand our understanding of the nature of speech perception, and have been working on commercialization of the use of air flow in enhancement of speech perception, as well as recording oral, nasal, and air flow outputs in speech without the use of masks or other stigmatizing measurement systems.
I am, as of 2017, working on a sonority scale for visual and tactile speech, as well as a both behavioral and brain research on audio-visual-tactile speech in coordination with the University of Canterbury’s Speech lab.
The end-goal is to form a true multi-sensory understanding of speech production and perception that does not ignore or minimize any of our senses.