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Eye-tracking reveals the effects of perceptual learning on neighboring phonemes Bridget Smith The Ohio State University

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Using time-course data to view phonological processes Bridget Smith The Ohio State University

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Background The interaction of speech perception and production in sound change Recreating sound change in a laboratory Measures changes in perception via lexical decision, identification tasks (RT and Accuracy), and eye-tracking paradigm 3

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Theory of sound change Phonetically-conditioned sound change begins with phonetic variation and ends with systematic change e.g., O.E. kirke, kiken -> M.E. church, chicken What happens in between? How gradual is it? Do lexical differences exist? Can it be conditioned by other non-phonetic factors? Can we reproduce it in a laboratory? 4

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Research Question Can we use perceptual learning and shadowing to reproduce sound change in a laboratory? After participants are exposed to a pronunciation variant, do they exhibit a change in perception and production consistent with a sound shift? (If yes, then there are many interesting questions about sound change to look at) 5

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Perceptual Learning When exposed to a pronunciation variant in familiar words, listeners incorporate the variant into their mental representation, temporarily (or sometimes long-term) thus changing the representation of that sound e.g., Norris, McQueen, & Cutler 2003 Ambiguous /s-f/ sound replaced segment in words with /s/ and words with /f/, boundary shift depended on which words. 6

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Shadowing/convergence When saying a word after hearing it pronounced, talkers change their productions to be more similar to those of the model talker. e.g., Goldinger et al 1998 Measured similarity using AXB task Later studies measured variables include VOT, F0, amplitude envelope, mean spectral frequency (center of gravity) 7

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Sub-questions Do participants undergo perceptual learning? Does this extend to new talkers? new words? Do participants undergo convergence with the trainers voices while shadowing? Is the change in pronunciation generalized to familiar words that they did not hear during training? Does the change in one sound affect other neighboring sounds? 8

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Experiment design Needed a source of variation that was not known to have any indexical value or be a sound change in progress Affrication of /tw/ Phonetically natural: stops before approximants frequently become affricated Historical precedent in English: /tr/ and /tj/ 9

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Experiment design Two likely trajectories of change: front or retracted frication: tsw- or tchw- tchw- common in observed variation parallels with of /tr/ and /tj/ physiological basis - rounding gesture for /w/ tsw- also possible, especially with dental /t/ c.f. OHG /t/ -> /ts/, even in front of /w/, e.g. zwei, or Japanese /t/ -> /ts/ before // 10

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tchw 11

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tsw 12

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tw 13

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tw (not as affricated) 14

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Ambient variation or sound change-in- progress? Known TV personalities who now say things like chwenty and chwitter and betchween: Rachel Maddow Michael Savage Michael Ian Black 15

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Links to videos http://www.youtube.com/watch?v=XS3rR5N5 vAA&t=49s http://www.youtube.com/watch?v=XS3rR5N5 vAA&t=49s http://youtu.be/D4rq53Ztvbg?t=4m18s 16

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Experiment 1 Design 45 /tw-/ initial English words 30 familiar-somewhat familiar 15 highly unfamiliar/archaic Necessitates different paradigm than traditional perceptual learning methods (e.g., Norris, McQueen & Cutler 2003). 17

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Experiment 1 Design Task 1: pre-training production and familiarity rating Participants read familiar and unfamiliar words at self controlled pace subset of training words, plus others: tw-, en-, vi-, t-, tr-, and str- words Rate familiarity of each 18

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Experiment 1 Design Familiarity Ratings: very familiar I know this word and use it somewhat familiar I know this word, but I may or may not use it myself neither familiar nor unfamiliar I may know this word, but do not use it somewhat unfamiliar I may have heard this word before, but have never used it very unfamiliar I have never heard or used this word before 19

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Experiment 1 Design Task 2: training/shadowing (en- vi- tw- words): Participants see the word on the screen Hear the word pronounced by trainers over headphones Say the word out loud after hearing it Hear the word again Silently read a definition See, hear, and say the word again Repeat in blocks of definitions and then sentences with the word in context 20

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Experiment 1 Design 21

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Experiment Design Hear each word 6 times, shadow 4 times 2 trainers for each word 1 male, 1 female Total 8 trainers 4 male, 4 female 3 conditions: Front tsw- Retracted tchw- Control tw- 22

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Experiment Design Task 3 - Lexical decision task: Using button box, choose whether stimulus is word or non-word 4 new talkers (2 male, 2 female) /tw/ target words: 28 trained, 15 untrained Half front tsw- variant, half retracted tchw- Non-words with variant, also vi- and en- words and non-words 23

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Experiment Design Task 4 Post-training production Participants read words off the screen for comparison to before pronunciations Task 5 Identification task Participants hear a stimulus and select whether they heard two chew or tsu Tests whether adaptation is extended to related environment /tu/ 24

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Overview Results Experiment 1 Lexical decision showed greater acceptance of variant that participants were trained on RT varies greatly by subject and other unknown factors, and cannot be directly compared Identification task showed generalization of training variant to /tu/ by boundary shifts Production results show convergence 25

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Perceptual learning 26 means 0.981 0.944 0.964 0.917 0.986 0.950 0.800 0.580 0.733 0.660 0.617 0.640 0.878 0.793 0.825 0.810 0.825 0.880

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Perceptual learning All subjects performed better on words containing the tchw- variant (F(1,67)=16.9, p