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Acoustic Continua and Phonetic Categories

Acoustic Continua and Phonetic Categories. Frequency - Tones. Frequency - Tones. Frequency - Tones. Frequency - Tones. Frequency - Complex Sounds. Frequency - Complex Sounds. Frequency - Vowels. Vowels combine acoustic energy at a number of different frequencies

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Acoustic Continua and Phonetic Categories

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  1. Acoustic Continua andPhonetic Categories

  2. Frequency - Tones

  3. Frequency - Tones

  4. Frequency - Tones

  5. Frequency - Tones

  6. Frequency - Complex Sounds

  7. Frequency - Complex Sounds

  8. Frequency - Vowels • Vowels combine acoustic energy at a number of different frequencies • Different vowels ([a], [i], [u] etc.) contain acoustic energy at different frequencies • Listeners must perform a ‘frequency analysis’ of vowels in order to identify them(Fourier Analysis)

  9. Frequency - Male Vowels

  10. Frequency - Male Vowels

  11. Frequency - Female Vowels

  12. Frequency - Female Vowels

  13. Synthesized Speech • Allows for precise control of sounds • Valuable tool for investigating perception

  14. Timing - Voicing

  15. Voice Onset Time (VOT) 60 msec

  16. English VOT production • Not uniform • 2 categories

  17. Perceiving VOT ‘Categorical Perception’

  18. Discrimination Same/Different

  19. Discrimination Same/Different 0ms 60ms

  20. Discrimination Same/Different 0ms 60ms Same/Different

  21. Discrimination Same/Different 0ms 60ms Same/Different 0ms 10ms

  22. Discrimination Same/Different 0ms 60ms Same/Different 0ms 10ms Same/Different

  23. Discrimination Same/Different 0ms 60ms Same/Different 0ms 10ms Same/Different 40ms 40ms

  24. Discrimination Same/Different 0ms 60ms Same/Different Why is this pair difficult? 0ms 10ms Same/Different 40ms 40ms

  25. Discrimination Same/Different 0ms 60ms Same/Different Why is this pair difficult? 0ms 10ms (i) Acoustically similar? (ii) Same Category? Same/Different 40ms 40ms

  26. Discrimination A More Systematic Test Same/Different 0ms 60ms Same/Different Why is this pair difficult? 0ms 10ms (i) Acoustically similar? (ii) Same Category? Same/Different 40ms 40ms

  27. Discrimination A More Systematic Test Same/Different 0ms 60ms 0ms 20ms 20ms 40ms Same/Different 0ms 10ms 40ms 60ms Same/Different 40ms 40ms

  28. Discrimination A More Systematic Test Same/Different D D 0ms 60ms 0ms 20ms D T 20ms 40ms Same/Different 0ms 10ms T T 40ms 60ms Same/Different Within-Category Discrimination is Hard 40ms 40ms

  29. Cross-language Differences L R

  30. Cross-language Differences L R L R

  31. Cross-Language Differences English vs. Japanese R-L

  32. Cross-Language Differences English vs. Hindi alveolar [d] retroflex [D] ?

  33. Russian -40ms -30ms -20ms -10ms 0ms 10ms

  34. Development of Speech Perception3 Classics

  35. Development of Speech Perception • Unusually well described in past 30 years • Learning theories exist, and can be tested… • Jakobson’s suggestion: children add feature contrasts to their phonological inventory during development Roman Jakobson, 1896-1982Kindersprache, Aphasie und allgemeine Lautgesetze, 1941

  36. Developmental Differentiation UniversalPhonetics Native Lg.Phonology Native Lg.Phonetics 0 months 6 months 12 months 18 months

  37. #1 - Infant Categorical Perception Eimas, Siqueland, Jusczyk & Vigorito, 1971

  38. Discrimination A More Systematic Test Same/Different D D 0ms 60ms 0ms 20ms D T 20ms 40ms Same/Different 0ms 10ms T T 40ms 60ms Same/Different Within-Category Discrimination is Hard 40ms 40ms

  39. English VOT Perception To Test 2-month olds Not so easy! High Amplitude Sucking Eimas et al. 1971

  40. General Infant Abilities • Infants’ show Categorical Perception of speech sounds - at 2 months and earlier • Discriminate a wide range of speech contrasts (voicing, place, manner, etc.) • Discriminate Non-Native speech contrastse.g., Japanese babies discriminate r-le.g., Canadian babies discriminate d-D

  41. Universal Listeners • Infants may be able to discriminate all speech contrasts from the languages of the world!

  42. How can they do this? • Innate speech-processing capacity? • General properties of auditory system?

  43. What About Non-Humans? • Chinchillas show categorical perception of voicing contrasts!

  44. #2 - Becoming a Native Listener Werker & Tees, 1984

  45. When does Change Occur? • About 10 months Janet Werker U. of British Columbia Conditioned Headturn Procedure

  46. When does Change Occur? • Hindi and Salishcontrasts testedon English kids Janet Werker U. of British Columbia Conditioned Headturn Procedure

  47. What do Werker’s results show? • Is this the beginning of efficient memory representations (phonological categories)? • Are the infants learning words? • Or something else?

  48. #3 - What, no minimal pairs? Stager & Werker, 1997

  49. A Learning Theory… • How do we find out the contrastive phonemes of a language? • Minimal Pairs

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