2. A STUDY ON PERCEPTUAL COMPENSATION FOR / /- FRONTING IN A MERICAN E NGLISH Reiko Kataoka February 14, 2009 BLS 35

3. PERCEPTUAL COMPENSATION FOR COARTICULATION Perceptual compensation for coarticulation: an effect of context-moderated perception that compensate for coarticulatory influence of the speech sounds. Perceptual correction (Ohala 1981: 182) Failure to compensate, erroneous compensation  misperception Why care perceptual compensation? To understand how humans achieve faithful sound transmission To understand how misperception could occur  sound change

4. EXAMPLES OF PERCEPTUAL COMPENSATION F1 of precursor influences [i]/[e] decision (Ladefoged & Broadbent, 1957) Speech rate influences [i]/[u] decision in [w_w] context (Lindblom & Studdert-Kennedy, 1967) Influence by: adjacent segment: Mann & Repp, 1980; Lotto & Kluender, 1998; Beddor & Krakow,1999; Harrington et al., 2008 Lexical status: Ganong, 1980; Elman & McClelland, 1988 Precursor sentence: Ohala & Shriberg, 1990

5. PREVIOUS STUDY ON ALVEOLAR / /- FRONTING (OHALA & FEDER, 1994) Stimuli: [i] – [u] continua (with following [də] or [bə]) Factors: Alveolar, Bilabial Acoustic or Noise Findings: 1) Listeners compensated for coarticulatory frongting in alveolar context. 2) Listeners did so both in Acoustic and Noise contexts VbəVbə VdəVdə

6. HYPOTHESIS H1: The /i-u/ boundary would be more leftward for alveolar context than for bilabial context. H2: The similar boundary shift would occur both in ‘Acoustic’ and ‘Noise’ conditions. H3: The boundary discrepancy would become progressively greater as speech rate increase from slow to medium to fast. Exploration: H4: Whether vowel perception is influenced by presence or absence of precursor sentence. (acoustic mode vs. speech mode?) H5: Whether Reaction Time (RT) for /u/-response is influenced by context or not. (perceptual contrast?)

7. STIMULI 10 equal-step /i/ - /u/ continuum (Praat) Separate a source from natural utterance. Apply a filter (5 peak fequencies and bandwiths) Duration = 100 msc Formant (Hz) bandwidth (Hz) F54500 250 F43500 200 F32319 150 F21200 100 F1 375 50

8. STIMULI 10 equal-step /i/ - /u/ continuum (Praat) cont. Variable F2 and F3 F3 2969 Hz ----------- 2319 Hz (0.18 Bark) F2 2372 Hz ----------- 1200 Hz (0.5 Bark) Vowel duration: 100 msc (also 80 msc and 120 msc) Amplitude contour first and last 15 ms F0 contour: 130  90 Hz F3: 2969 2888 2808 2732 2658 2586 2516 2448 2382 2319 (Hz) F2: 2372 2201 2042 1895 1759 1632 1513 1402 1298 1200 (Hz)

9. STIMULUS CVC Add onset and coda to the vowel Alveolar: [dit] – [dut] Alveolar in Noise: [NiN] – [NuN] Bilabial: [bip] – [bup] Bilabial in Noise: [NiN] – [NuN](Vowel onset to C2 release = 170 msc)

10. EXPERIMENTAL DESIGN w/o Precursor: Stimulus presented in isolation Task: two-alternative forced-choice between /i/ and /u/ w/Precursor: Stimulus presented after “I guess the word is _____” Trials: 10 tokens x 4 repetition = 40 trials per cell Block: Context – blockedAcoustic vs. Noise – mixed; Fast, Medium, Slow – blocked Listeners: Native speakers of Am-Engl. (n=32: 18F, 14M; 19-49 yrs old) Context ConditionsAlveolar ‘deet’ /‘doot’ Bilabial ‘beep’ /‘boop’ w/o precursor Acoustic (100)[dVt][bVp] Noise (100)[NVN] w/ precursor Fast (800-80)[dVt][bVp] Med. (1000-100)[dVt][bVp] Slow (1200-120)[dVt][bVp] H1 H3 H2 Q1 Q2: RT

11. THIS IS HOW THE EXPERIMENT GOES (1) Acoustic Noise Press [1] Press [5] for for ‘deet’ ‘doot’

12. THIS IS HOW THE EXPERIMENT GOES (2) Acoustic Noise Press [1] Press [5] for for ‘beep’ ‘boop’

13. THIS IS HOW THE EXPERIMENT GOES (3) Fast Medium Slow Press [1] Press [5] for for ‘deet’ ‘doot’

14. RESULTS: NOISE VS. ACOUSTIC * CONTEXT Percentage of /u/-Response by Context and Condition NoiseAcustic /u/-Response (%) Stimulus Step Number

15. RESULTS: NOISE VS. ACOUSTIC * CONTEXT (RT) Reaction Time for /u/-response Effect of Contexts (Paired T-Test) N: [t=-0.69 (31), p=0.499] R: [t=-1.60 (31), p=0.123] 684 710 643 694

16. RESULTS: PRECURSOR * CONTEXT Percentage of /u/-Response by Condition and Context t=0.91 (31), p=0.371 t=2.68 (31), p=0.012 * /u/-Response (%)

17. RESULTS: PRECURSOR * CONTEXT (RT) Reaction Time for /u/-response 643 694695 755 Effect of Contexts (Paired T-Test) Without: [t=-1.6 (31), p=0.120] With: [t=-2.26 (31), p=0.031] *

18. RESULTS: SPEECH RATE * CONTEXT Percentage of /u/-Response by Context and Condition Effect of Contexts (Paired T-Test) Slow: [t=-0.078 (31), p=0.938] Medium: [t=2.684 (31), p=0.012] * Fast: [t=4.657 (31), p<0.001] * /u/-Response (%) Fast Slow Medium Stimulus Number

19. RESULTS: SPEECH RATE * CONTEXT (RT) Reaction Time for /u/-response 634667661 755 695 611 Effect of Contexts (Paired T-Test) Slow: [t=-0.157 (31), p=0.876] Medium: [t=-2.257 (31), p=0.031]* Fast: [t= 0.686 (31), p=0.498

20. SUMMARY AND DISCUSSIONS No compensation when consonantal contexts were replaced by white noise and “assumed” contexts were given visually. Degree of boundary shift varies across stimuli and experimental condition: Greater shift with precursor sentences than without it. Progressively greater boundary shift as speech rate increases Reaction Time for /u/-response Significant context effect (A <B) in majority of conditions  Degree of Compensation for coarticulation may be influenced by speechlike-ness of the stimuli. Compensation is triggered when linguistic expectation plays a role in perception.  Compensation could be incomplete.  Perceptual Compensation may be related to contrast enhancement.  On the linguistic theory of sound change: Assimilatory sound change by incomplete correction?

21. Thank you!!