Science Student Spotlight: Rion Iwasaki

January 8, 2020

Rion Iwasaki student

Rion Iwasaki is a third-year, level II student in the Ph.D. Program in Speech-Language-Hearing Sciences at the Graduate Center (GC), CUNY. He is a member of Speech Production, Acoustics, and Perception Laboratory (SPAPL), directed by his Ph.D. adviser, Dr. Douglas H. Whalen. He is also a student associate at Haskins Laboratories in New Haven, CT, where Dr. Whalen is a Vice President of Research and a Senior Scientist.

Rion is from Tokyo, Japan. His given name, Rion (理音), is written with Chinese characters meaning “reasoning” (理) and “sounds” (音). Coincidentally, he got interested in speech sounds. He is particularly interested in how we produce speech sounds, the relationship between the movements of articulators and resultant speech sounds, and how this relationship differs across languages. He received an M.A in linguistics at Sophia University in Tokyo, Japan. He also studied in a speech pathology course at Sophia University while working on his master’s degree. When he joined the program at the GC, he received a two-year science fellowship (2017-2019).

This academic year (2019-2020), he received two research grants from the GC for his pre-dissertation project, (a) Doctoral Student Research Grant and (b) Provost’s Pre-dissertation Research Fellowship. His pre-dissertation project focuses on the tongue movements during the articulation of so-called “devoiced” vowels in Tokyo Japanese. Vowels usually have three articulatory aspects, (a) phonation, and some individual-vowel specific (b) lip and (c) lingual articulation. However, in Tokyo Japanese, high vowels ([i] and [u]) can be devoiced, that is, articulated without phonation in certain phonetic contexts. There is a controversy on whether devoiced vowels are just unphonated or deleted entirely (i.e., no lip and lingual specification). In his project, Rion uses ultrasound to see how the tongue moves during the articulation of both devoiced and voiced high vowels and to compare the tongue configurations between the two. If devoiced vowels are just unphonated, there should be no difference in the tongue configurations between devoiced and voiced vowels. In contrast, if devoiced vowels are deleted entirely, the lingual articulation could be different between the two. The deletion of devoiced vowels implies that a sound change is coming in Tokyo Japanese: Even though Japanese is believed to have typically only open syllables, where a single consonant precedes a vowel, the deletion of devoiced vowels means that Japanese may permit a certain sequence of consonants in certain phonetic contexts.

Utrasound device
A diagnostic ultrasound device in Speech Production, Acoustics and Perception Lab in Graduate Center with a tongue image. The white line in the middle represents the tongue surface on the midsagittal plane.

During the summer and fall this year, Rion collected articulatory data from native speakers of Tokyo Japanese living in New York City. Speakers produced word pairs contrasting in the voicing realization of the vowels (voiced and devoiced ones) while putting their chin on an ultrasound transducer. The resultant ultrasound imaging showed tongue contours during articulation on the sagittal plane. The study also employed an optical tracking technique to correct any movements the speakers made during the experiment. The data analysis of this project mainly had two parts: (a) tracing the tongue contours on ultrasound images and (b) comparing the tongue configurations between devoiced and voiced vowels by quantifying the traced tongue contours. Results so far show that devoiced /i/ produced in nonsense words has the same tongue configuration as voiced /i/, at least in two phonetic contexts analyzed in this project. This indicates that devoiced /i/ produced in the context of nonsense words are just unphonated and that the vowels are still present even when devoiced (i.e., not deleted).

This December, Rion successfully presented his result at the Acoustic Society of America meeting in San Diego. Upon receiving many informative comments during the presentation, Rion is more than eager to continue working on the lingual articulation of Japanese devoiced vowels in his dissertation work, especially by examining devoiced /i/ produced in other phonetic contexts as well as devoiced /u/, the other high vowel which can be devoiced in Tokyo Japanese.