2. Distinguishing phonetic processing and motor processing: Evidence from instrumental analysis of acquired speech impairment Adam Buchwald New York University buchwald@nyu.edu 18 June 2009 DEPARTMENT OF COMMUNICATIVE SCIENCES AND DISORDERS

3. 2 Spoken language production Producing spoken language requires many levels and processes to be orchestrated –Lexical access in long-term memory; working memory; articulatory planning and implementation Today: relationship between phonetic planning and motor programming –Guided by discussion of: Phonetic processing/impairment vs. motor processing/impairment in Apraxia of Speech Focus on: Consonant clusters

4. 3 Phonetic plans & motor programs “Phonetic plan” ≡ sound structure representation –includes detail re: temporal overlap of gestures, phasing relations –gestural score in articulatory phonology (Browman & Goldstein, 1986,1988, et seq.) As in the output of phonetic encoding in some processing accounts (Levelt et al., 1999; Cholin et al., 2004, 2006) “Motor programs” ≡ detailed representation encoding temporal overlap of articulators Inter-articulator coordination Are these created by separate systems? What are the properties of impairment to these systems?

5. 4 Consonant clusters Syllables with onset clusters contain complex structure and phasing –Onset consonants are coupled to vowels (Browman & Goldstein, 1988; Byrd, 1996) Center of consonant timed to onset of vowel Complicated by presence of a cluster; in English, center of cluster timed to onset of vowel –Multiple possible ‘repairs’ (or simplifications) Deletion; changing phasing relation; inserting a vowel Questions regarding 2 different aphasic/apraxic speaker How are the consonant clusters repaired? What properties determine the nature of the repair?

6. 5 VBR Buchwald, Rapp & Stone, 2007 57, RH, F Suffered CVA at 51 –large LH fronto-parietal infarct involving posterior frontal lobe, including Broca's area, pre- and post-central gyri and the SMG Dysfluent spoken production, mainly single-word utterances

7. 6 VBR and schwa insertion Difficulty producing complex onsets –Produces consonant clusters with a vowel inserted between the two consonants –e.g., bleed  [bəlid] Robust pattern –Occurs with different modalities of presentation (naming, repetition, reading) What is the nature of these errors? –Epenthesis vs. Articulatory (mis)timing believe

8. 7 Epenthesis vs. Mistiming Epenthesis C 1 C 2 Vowel inserted in gestural score Gestural mistiming C 1 C 2 Consonant gestures mistimed –Audible release of C 1 Open vocal tract Target: C 1 C 2 ə ə onset targetrelease

9. 8 Ultrasound study Examine articulations to see whether inserted schwa is like lexical schwa Produce word pairs: bleed-believe –Matched on C1, C2, and stressed V Compare tongue contours –If epenthesis: inserted schwa = lexical schwa –If mistiming: inserted schwa ≠ lexical schwa

10. 9 Inserted schwa = Lexical schwa Back Tongue Position Front Red – Inserted Blue – Lexical Within-category differences EQUAL across-category differences

11. 10 Consonant cluster repair: schwa epenthesis The inserted vowel is the result of epenthesis –Articulatory data from ultrasound: tongue contour of inserted vowel similar to lexical vowel Similar variability between vowels and within vowel types Supported by acoustic data (duration, variability, co- articulation) Systematic epenthesis repair of obstruent- sonorant clusters –Removes structural (and articulatory) complexity by adding schwa to phonetic plan

12. 11 DLE Buchwald, Rapp & Miozzo, 2009 72 year old aphasic/apraxic speaker Spoken production limited – short phrases; labored Produces systematic consonant cluster errors in deletion of /s/ from /s/-stop and /s/-nasal clusters Question: at what level does deletion take place? –Is deletion part of phonetic plan or does it occur during generation of motor program? smashmash steer tier deer

13. 12 Phonetic errors vs. motor errors Phonetic planning precedes motor programming If phonetic plan has no /s/, then the token has singleton onset consonant and should be produced accordingly If phonetic plan has /s/ and deletion occurs at motor level, then timing should be appropriate for cluster –Compare tokens with deleted /s/ to singletons –Use acoustic properties of language to help with this /s/-stops: VOT in spin is closer to bin than pin /s/-nasals: nasal duration in snail shorter than nasal in nail –Paired comparisons of target clusters with singletons e.g., speak vs. peak, beak e.g., smash vs. mash

14. 13 Hypotheses Phonetic planning errors –Stops in deletions more similar to singleton voiceless stops Reflects /s/ being absent from phonetic plan –Nasals in deletions same duration as singleton nasals Reflects /s/ being absent from phonetic plan Motor programming errors –Stops in deletions more similar to singleton voiced stops Reflects /s/ being absent from phonetic plan –Nasals in deletions shorter than singleton nasals Reflects /s/ being absent from phonetic plan

15. 14 /s/-stop and singleton stop VOT What factors increase the likelihood of repair? LabialAlveolarVelar (s)-stop 27.544.468.5 voiceless 30.543.977.8 voiced 21.933.844.3 N7910325 Labial Alveolar Velar

16. 15 /s/-nasal duration Nasal duration and VOT both reflect the production of a phonetic plan generated without an /s/

17. 16 Phonetic planning errors These two cases of apraxia both exhibit phonetic planning errors –Does not mean these are the only possible errors; just happens to be the case here What to do with these errors? –Examine factors that influence the incidence and nature of these errors to learn about phonetic planning system –For each individual, we see effects of (relatively abstract) phonological representations on their errors

18. 17 Phonological effects: VBR VBR: epenthesis errors in obstruent-sonorant clusters –Words with C/j/ onset (e.g., cute) argued to have complex vocalic diphthong (/ju/) rather than cluster If #Cw sequences (as in queen, quote) are clusters: –Should be repaired via epenthesis If #Cj as in cute, music are clusters: –Should be repaired via epenthesis, as other clusters –Never repaired via epenthesis –Repaired via deletion: /kjut/  [kut] cutemusic

19. 18 Phonological effects: DLE DLE: /s/-deletion in obstruent-obstruent and obstruent-nasal clusters –English has a few other obstruent-obstruent and obstruent-nasal onsets (/ ∫ /-initial) If DLE’s ‘repair’ can be expressed over natural classes, should similarly affect these sequences –In addition, other sonority-based descriptions affect error rate – deletion very rare in /sl/ and / ∫ r/ clusters

20. 19 Summary and future directions Instrumental analyses of apraxic/aphasic speech can show errors of phonetic planning –Phonetic planning errors appear to be affected by phonological properties, leading to systematic sound structure repairs Future work –Explore error systematicity as a way to determine whether errors –Extend analyses to other impairments, particularly motor programming impairment and children with speech sound impairments (with HBK, CR) –Incorporate other speech production instruments (EMMA? Real- time MRI?)

21. 20 Acknowledgements Brenda Rapp Maureen Stone Michele Miozzo Paul Smolensky VBR DLE Cettina Chiarelli Cristina Sanchez