Wodzinski, S.M., Hardin, S.A., Frisch, S.A., & Stearns, A.M., University of South Florida

1. Data collection techniques in the USF speech production and perception laboratory,and their reliability Wodzinski, S.M., Hardin, S.A., Frisch, S.A., & Stearns, A.M., University of South Florida frisch@cas.usf.edu This work supported by NIH-NIDCD R03 06164

2. Ideal Recording Setup • Head stabilized • Head location fixed • Probe location (relative to head) fixed • Stone (2004): Need consistent point of reference in images for measurement (cf. Whalen 2004 HOCUS system)

3. Ideal Recording Setup • Jaw able to move freely • If probe location is fixed, jaw contact with probe makes this difficult • Need for ‘compressible acoustically transparent standoff’ (Stone 2004) • Compressible so jaw can move • Acoustically transparent so it does not interfere with ultrasound beam

4. USF Ultrasound Lab

5. Head Stabilization • Head location fixed by a ‘halo’ • Current version pieced together with rods and clamps borrowed from the physics laboratory • Similar in spirit to the HATS system (Stone & Davis 1995) • FYI, body movement minimized by placing participant in a non-wheeled straight backed chair

6. Head stabilizing ‘halo’

7. Head Stabilization • Participant rests forehead against headrest (padded dowel) • Side and rear padded dowels adjusted to press lightly on the head • This arrangement discourages head movement, but does not keep the head held absolutely fixed

8. Padded dowel

9. Demonstration of ‘halo’ on SAH

10. Compressible acoustically transparent standoff (CATS) • Probe held by clamp on a cross-bar within the same apparatus • Raised to fit snugly under the chin • CATS between probe and chin allows jaw movement without disturbing the image • Currently, CATS held on by rubber bands • Unfortunately, CATS does provide some resistance to jaw movement

11. CATS • CATS is a gel computer wrist rest • Trial and error to find a good wrist rest for this purpose • Recommend something that comes inside a cloth sleeve • Some rests within a non-transparent plastic sleeve have a more gelatinous interior and do not hold shape without the sleeve (yuck!) • Watch for air bubbles

12. CATS in USF lab

13. Other Info from Our Lab • Using Aloka SSD-1000 • Record directly to computer with Canopus ADVC-1394 • Have a computer with two 17” screens for data analysis (not pictured) • Second hard drive and DVD writer for storage and archiving

14. Measurement • View video with Adobe Premiere • All studies focusing on stops /k, g, t, d/ • Identify closure visually with reference to the waveform in Premiere • Extract frame to Photoshop for measurement

15. Reliability of Measures • Hardin (in progress) evaluating the reliability of hand measures of stop consonants • Data presented today from a reliability study of velar stop closure measures in Wodzinski (2004)

16. Wodzinski (2004) • Presented (in part) at Ultrafest II • Study examined fronting of velar stops by three normal adult participants • Found velar stop closure location (quantified by an angle measure) correlated strongly with the frontness of the following vowel (quantified by F2)

17. /gev/ /gu/

18. Reliability of Measures • Raters • 2 female research assistants • Enrolled in the USF speech-language pathology master’s degree program • Trained in phonetics and speech science, and experienced in ultrasound measurement

19. Reliability of Measures • Procedure • Raters used the same computer programs and settings • Measurements done completely independently (nearly a year apart) • Raters given same criteria for measurement

20. Reliability of Measures • Criteria used by researchers to identify dorsum closure location: • Direction of tongue movement into and out of closure • Tongue flattening against hard palate at closure location • Brighter margin at edge of tongue surface during closure (probably because that portion of the tongue is no longer in motion)

21. Reliability of Measures • Measurement procedure • Closure is identified • The most anterior and posterior points of closure are marked • A midpoint is determined between the points by computer algorithm • The dorsal angle is derived between midpoint and the center point of the probe at the bottom of the ultrasound image

22. Results (Closure frame) • Raters compared for selection of video frame to measure as midpoint of velar closure • Analysis of difference in frame number between repeat of measure (SH) and original measure (SW)

23. Results (Closure frame)

24. Results (Closure points) • Raters compared on position of anterior and posterior closure points • Word data • Anterior point avg 3.2 mm difference • Posterior point avg 6.2 mm difference • Nonword data • Anterior point avg 3.1 mm difference • Posterior point avg 5.2 mm difference

25. Results (Dorsum angle) • Resulting dorsum angle compared between raters • Significant differences between dorsum angle measures between raters • Word data SH < SW by 1.6º [t(119) = 10.3, p < 0.01] • Nonword data SH < SW by 0.7 º [t(171) = 4.1, p < 0.01]

26. Results (Dorsum angle) • However, raters agreed in the overall pattern for how dorsum angle related to following vowel • Correlation between raters • Word data, r = 0.93 • Nonword data, r = 0.95

27. Results (Dorsum angle) • Qualitatively, the resulting analysis of coarticulation between vowel and velar angle is the same for both raters

28. Summary (Reliability) • There were quantitative differences between raters in their measures of velar closures • Inherently imprecise methodology? • Strategies of raters for identifying closure? • Experience with measuring ultrasound images? • Nonword data appeared more consistent than word data between raters… why?

29. Summary (Lab tech) • The USF ultrasound lab has functional but probably not permanent solutions to the problems of head stabilization, probe stabilization, and a compressible standoff • Though these solutions are temporary, we have collected informative data on the articulation of stop consonants

30. Question • At USF, we have had to throw away about 50% of our participants because of ‘fuzzy’ tongue, or image drop out in the production of /k, g, t, d/ • Is there a modification of apparatus that would increase # of usable participants? • Is there a modification of collection technique that would increase # of useable participants?