1 Probing the Big Bang with ultrasound: Retraction of /s/ in English Adam Baker, Jeff Mielke, Diana Archangeli University of Arizona Supported by James S. McDonnell Foundation # BBMB

2 Retraction of /s/ Various sources report the retraction of /s/ in / st  / clusters (Labov 1994, Shapiro 1995, Lawrence 2000, Joseph & Janda 2001). Various sources report the retraction of /s/ in / st  / clusters (Labov 1994, Shapiro 1995, Lawrence 2000, Joseph & Janda 2001). also in / sk  /, /  # s / clusters. also in / sk  /, /  # s / clusters. / s / becomes more / S /-like. / s / becomes more / S /-like. Clear social boundaries have not yet been determined, although the change is fairly widespread. Clear social boundaries have not yet been determined, although the change is fairly widespread.

3 Big Bang Model The Big Bang model (Joseph & Janda 2001) suggests that changes are initiated by phonetic factors, but propagated by social factors. The Big Bang model (Joseph & Janda 2001) suggests that changes are initiated by phonetic factors, but propagated by social factors. Crucially, the phonetic motivation is not necessarily present at all stages of the change. Crucially, the phonetic motivation is not necessarily present at all stages of the change.

4 Hypothesis We expect a phonetic motivation for the sound change. We expect a phonetic motivation for the sound change. Coarticulatory effect of /  / Coarticulatory effect of /  / Various productions of /  / exist (Delattre & Freeman 1968, Tiede et al. 2004, Mielke et al. 2006) Various productions of /  / exist (Delattre & Freeman 1968, Tiede et al. 2004, Mielke et al. 2006) Different /  / production strategies must produce different coarticulation. Different /  / production strategies must produce different coarticulation.

5 Hypotheses We expect this to affect the initiation of a sound change. We expect this to affect the initiation of a sound change. e.g. bunching favors /s/-retraction more than retroflexion, or perhaps vice versa e.g. bunching favors /s/-retraction more than retroflexion, or perhaps vice versa Specifically: A subset of /  /’s encourage /s/-retraction. Specifically: A subset of /  /’s encourage /s/-retraction. But, retractors can have any /  /, since they retract for top-down reasons. But, retractors can have any /  /, since they retract for top-down reasons.

6 Study We conducted an ultrasound and acoustic study of retractors and non-retractors. We conducted an ultrasound and acoustic study of retractors and non-retractors. Goals Goals describe s-retraction articulatorily and acoustically describe s-retraction articulatorily and acoustically Is it [ S ]trict, [ s  ]trict, [  ]trict, or … ? Is it [ S ]trict, [ s  ]trict, [  ]trict, or … ? test aforementioned hypotheses test aforementioned hypotheses

7 Methods 32 U of A undergraduates recorded 32 U of A undergraduates recorded 6 discarded either for imaging poorly, or technical problems 6 discarded either for imaging poorly, or technical problems 16 non-retractors, 10 retractors 16 non-retractors, 10 retractors Age range: yrs., mean = 18.7 Age range: yrs., mean = 18.7 Produced words with initial s(C)(  ) and S (  ) sequences, with following / i, I, Q, u /. Produced words with initial s(C)(  ) and S (  ) sequences, with following / i, I, Q, u /. Two items from each combination (e.g. stack and stab). Two items from each combination (e.g. stack and stab). Four tokens of each item. Four tokens of each item.

8 Methods Simultaneous recording of: Simultaneous recording of: ultrasound video ultrasound video facial profile video (for lips) facial profile video (for lips) acoustic signal acoustic signal The hard palate was imaged. The hard palate was imaged. Subjects were impressionistically classified as retractors or non-retractors. Subjects were impressionistically classified as retractors or non-retractors.

9 Measurement: Ultrasound Ultrasound frames chosen by hand: Ultrasound frames chosen by hand: all sibilants all sibilants /  / in / st  / tokens. /  / in / st  / tokens. Tongue outlines were produced with the Palatoglossatron software. Tongue outlines were produced with the Palatoglossatron software. Each subject’s palate was overlaid on the tongue tracing. Each subject’s palate was overlaid on the tongue tracing. With correction for head and transducer movement. With correction for head and transducer movement.

10 Measurement: Acoustic Centroid frequency distinguishes / s / from / S /; / s / has higher centroid, / S / lower. Centroid frequency distinguishes / s / from / S /; / s / has higher centroid, / S / lower. Centroid frequency: Centroid frequency: Weighted average over 1-10 kHz Weighted average over 1-10 kHz 5 ms analysis window 5 ms analysis window Average of centroids of spectra from the middle half of the sibilant Average of centroids of spectra from the middle half of the sibilant 2 ms time step 2 ms time step Tokens were averaged across item. Tokens were averaged across item.

11 Results: Description Ultrasound images of retracted /s/ fall into three categories: Ultrasound images of retracted /s/ fall into three categories: canonical retraction canonical retraction palatalization palatalization retroflexion retroflexion

12 Subj. 15 Retractor /s/ from /st/ clusters Retraction

13 Subj. 15 Retractor / s / from / st  / clusters Retraction

14 Subj. 15 Retractor / S / Retraction

15 Subj. 15 Retractor /s/ from /st  / clusters / S / Retraction

16 Subj. 21 Retractor /s/ from /st/ clusters Palatalization

17 Subj. 21 Retractor /s/ from /st  / clusters Palatalization

18 Subj. 21 Retractor / S / Palatalization

19 Subj. 21 Retractor /s/ from /st  / clusters / S / Palatalization

20 Subj. 29 Retractor /s/ from /st/ clusters Retroflexion

21 Subj. 29 Retractor /s/ from /st  / clusters Retroflexion

22 Subj. 29 Retractor / S / Retroflexion

23 Subj. 29 Retractor /s/ from /st  / clusters / S / Retroflexion

24 Results: Description Articulatorily, “retracted /s/” is not a unified entity. Articulatorily, “retracted /s/” is not a unified entity. Is retracted /s/ different from / S / acoustically? Is retracted /s/ different from / S / acoustically?

25 Results: Description Retracted /s/ has higher centroid frequency than / S /. Retracted /s/ has higher centroid frequency than / S /. t-test indicates significance F(1,182) = t-test indicates significance F(1,182) = p < 2.2 x /str/ /S//S/

26 Results: Description Across-subject comparison was accomplished with normalization Across-subject comparison was accomplished with normalization set [ s ] to 1 set [ s ] to 1 set [ S ] to 0 set [ S ] to 0 place / s / from / st  / in between place / s / from / st  / in between Pooled data from retractors and non- retractors yield a smooth progression from [ s ] to [ S ]. Pooled data from retractors and non- retractors yield a smooth progression from [ s ] to [ S ]. not a sigmoidal plot not a sigmoidal plot

27 Ranked normalized / st  / [s] -like [S] -like

28 Results: Description This indicates either This indicates either a phonetically gradient change a phonetically gradient changeOR a categorical change involving very small quanta a categorical change involving very small quanta

29 Paradigm We study phonetic effects in today’s non- retractors (no top-down confound) We study phonetic effects in today’s non- retractors (no top-down confound) Assumption: non-retractors are representative of the population before the retraction change (with respect to this change) Assumption: non-retractors are representative of the population before the retraction change (with respect to this change) Use articulatory data to generate predictions to be tested acoustically. Use articulatory data to generate predictions to be tested acoustically.

30 Phonetic Motivation Do different /  / production strategies affect /s/ differently? Do different /  / production strategies affect /s/ differently? Surprise: the /#st_/ context strongly favors bunching of /  /. Surprise: the /#st_/ context strongly favors bunching of /  /. Need other means to compare /  /’s. Need other means to compare /  /’s. Two articulatory indicators of coarticulation: Two articulatory indicators of coarticulation: Narrow palatal constriction in /  / Narrow palatal constriction in /  / Similarity between /  / and /s/ Similarity between /  / and /s/

31 Palatal Constriction Hypothesis Hypothesis Coarticulation in a / st  / cluster results in a more retracted / s / when the /  / involves a close palatal constriction. Coarticulation in a / st  / cluster results in a more retracted / s / when the /  / involves a close palatal constriction. Test Test Non-retracting subjects were judged to have a wide or narrow palatal constriction in /  /. Non-retracting subjects were judged to have a wide or narrow palatal constriction in /  /.

32 Subj. 25 Non-retractor /  / from /st  / clusters No palatal constriction

33 Subj. 30 Non-retractor /r/ from /str/ clusters Palatal constriction

34 Results: Palatal Constriction Wider constriction /  / subjects had lower /s/ (~217 Hz) than narrow. Wider constriction /  / subjects had lower /s/ (~217 Hz) than narrow. t-test indicates significance F(1,78) = t-test indicates significance F(1,78) = p <

35  / s Similarity Hypothesis Hypothesis A larger difference in the tongue postures for /  / and / s / will result in greater coarticulation. A larger difference in the tongue postures for /  / and / s / will result in greater coarticulation. Speakers would have to accomplish a larger postural change in a comparable time frame. Speakers would have to accomplish a larger postural change in a comparable time frame. Test Test /  / from / st  / clusters was compared to / s / from / st / clusters. Tongue shapes were judged to be similar or dissimilar. /  / from / st  / clusters was compared to / s / from / st / clusters. Tongue shapes were judged to be similar or dissimilar.

36 Subj. 24 Non-retractor /  / from /st  / clusters  / s Dissimilar  / s

37 Subj. 24 Non-retractor /s/ from /st/ clusters  / s Dissimilar  / s

38 Subj. 5 Non-retractor /  / from /st  / clusters  / s Similar  / s

39 Subj. 5 Non-retractor /s/ from /st/ clusters  / s Similar  / s

40 Results: Similarity Dissimilar  / s pairs yielded lower /s/ (~256 Hz) than similar. Dissimilar  / s pairs yielded lower /s/ (~256 Hz) than similar. t-test indicates significance F(1,78) = t-test indicates significance F(1,78) = p <

41 Results: Similarity A speaker’s particular /  / (and / s /) affect degree of coarticulation in / st  / clusters. A speaker’s particular /  / (and / s /) affect degree of coarticulation in / st  / clusters. A little more complex than originally imagined… A little more complex than originally imagined… … and relative to different articulations of both / s / and /  /. … and relative to different articulations of both / s / and /  /. Sub-population of non-retractors has coarticulation in the direction of retraction. Sub-population of non-retractors has coarticulation in the direction of retraction.

42 Results: Retractor coarticulation Not all retractors have coarticulatory motivation for retraction. Not all retractors have coarticulatory motivation for retraction. Some have quite similar  / s pairs. Some have quite similar  / s pairs.

43 Subj. 1 Retractor / s / from / st / clusters  / s Similar  / s

44 Subj. 1 Retractor /  / from /st  / clusters  / s Similar  / s

45 Results: Retractor coarticulation Do retractors have any coarticulatory motivation? Do retractors have any coarticulatory motivation? Pooled data, ANOVA with factors Retractor (y/n) and  / s shape (similar/dissimilar) Pooled data, ANOVA with factors Retractor (y/n) and  / s shape (similar/dissimilar) Both main effects significant Both main effects significant No significant interaction No significant interaction The coarticulatory effect is present only for some retractors. The coarticulatory effect is present only for some retractors.

46 Non-retractorsRetractors

47 Results: retractors have similar variation to non-retractors Some retractors do not have (much) coarticulatory motivation for retraction. Some retractors do not have (much) coarticulatory motivation for retraction. These retractors must be retracting for top- down reasons. These retractors must be retracting for top- down reasons. Other retractors have coarticulatory motivation for retraction Other retractors have coarticulatory motivation for retraction But this alone does not account for the extent of their retraction. But this alone does not account for the extent of their retraction. These retractors have top-down and bottom- up motivation for retraction. These retractors have top-down and bottom- up motivation for retraction.

48 Non-retractorsRetractors

49 Conclusion / s / retraction appears to be a gradual sound change. / s / retraction appears to be a gradual sound change. Non-retractors with dissimilar  / s productions have lower / s / productions in /str/ clusters. Non-retractors with dissimilar  / s productions have lower / s / productions in /str/ clusters. Retractors can have the same coarticulatory pattern, but this cannot fully account for their pronunciations. Retractors can have the same coarticulatory pattern, but this cannot fully account for their pronunciations.

50 Conclusion Big Bang prediction Our Finding Phonetic motivation at outset of change. Subset of  / s productions lower centroid freq. of / s / in non-retractors. Change can then spread by social factors. Retractors exhibit a range of  / s production, not necessarily only those conducive to retraction. These findings support the Big Bang model of sound change. These findings support the Big Bang model of sound change.