Perceptual learning and convergence in sound change

Eye-tracking reveals the effects of perceptual learning on neighboring phonemesBridget SmithThe Ohio State UniversityUsing time-course data to view phonological processesBridget SmithThe Ohio State UniversityBackgroundThe interaction of speech perception and production in sound changeRecreating sound change in a laboratoryMeasures changes in perception via lexical decision, identification tasks (RT and Accuracy), and eye-tracking paradigm3Theory of sound changePhonetically-conditioned sound change begins with phonetic variation and ends with systematic changee.g., O.E. kirke, kiken -> M.E. church, chickenWhat 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?

4Research QuestionCan 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)5Perceptual LearningWhen 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 sounde.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.6Shadowing/convergenceWhen 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 1998Measured similarity using AXB taskLater studies measured variables include VOT, F0, amplitude envelope, mean spectral frequency (center of gravity)7Sub-questionsDo 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?8Experiment designNeeded a source of variation that was not known to have any indexical value or be a sound change in progressAffrication of /tw/Phonetically natural: stops before approximants frequently become affricatedHistorical precedent in English: /tr/ and /tj/

9Experiment designTwo 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 //

10tchw11

tsw

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tw

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tw (not as affricated)

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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 MaddowMichael SavageMichael Ian Black

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Links to videoshttp://www.youtube.com/watch?v=XS3rR5N5vAA&t=49s

http://youtu.be/D4rq53Ztvbg?t=4m18s

16Experiment 1 Design45 /tw-/ initial English words30 familiar-somewhat familiar15 highly unfamiliar/archaic

Necessitates different paradigm than traditional perceptual learning methods (e.g., Norris, McQueen & Cutler 2003). 17Experiment 1 DesignTask 1: pre-training production and familiarity ratingParticipants read familiar and unfamiliar words at self controlled pacesubset of training words, plus others: tw-, en-, vi-, t-, tr-, and str- wordsRate familiarity of each18Experiment 1 DesignFamiliarity Ratings:very familiar I know this word and use itsomewhat familiar I know this word, but I may or may not use it myselfneither familiar nor unfamiliar I may know this word, but do not use itsomewhat unfamiliar I may have heard this word before, but have never used itvery unfamiliar I have never heard or used this word before19Experiment 1 DesignTask 2: training/shadowing (en- vi- tw- words):Participants see the word on the screenHear the word pronounced by trainers over headphonesSay the word out loud after hearing itHear the word againSilently read a definitionSee, hear, and say the word againRepeat in blocks of definitions and then sentences with the word in context20Experiment 1 Design

21Experiment DesignHear each word 6 times, shadow 4 times2 trainers for each word 1 male, 1 femaleTotal 8 trainers 4 male, 4 female3 conditions:Front tsw-Retracted tchw-Control tw-22

Experiment DesignTask 3 - Lexical decision task:Using button box, choose whether stimulus is word or non-word4 new talkers (2 male, 2 female)/tw/ target words: 28 trained, 15 untrainedHalf front tsw- variant, half retracted tchw-Non-words with variant, also vi- and en- words and non-words23Experiment DesignTask 4 Post-training productionParticipants read words off the screen for comparison to before pronunciationsTask 5 Identification taskParticipants hear a stimulus and select whether they heard two chew or tsuTests whether adaptation is extended to related environment /tu/

24Overview Results Experiment 1Lexical decision showed greater acceptance of variant that participants were trained onRT varies greatly by subject and other unknown factors, and cannot be directly comparedIdentification task showed generalization of training variant to /tu/ by boundary shiftsProduction results show convergence25Perceptual learning

26means 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 0.880Perceptual learningAll subjects performed better on words containing the tchw- variant (F(1,67)=16.9, p