A Reanalysis of Anatomical Changes for Language

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Recent studies have suggested that various anatomical changes, such as the widening of the hypoglossal canal, the descent of the larynx, and the loss of air sacs, are prerequisites for speech or occurred due to selective pressure on speech. Such studies have been used to suggest that Homo neanderthalis as well as early Homo sapiens were capable of speech. However, using a broad literature review of multimodal languages, such as whistle languages, and the articulation processes behind prosodic features, I will show that such studies ignore various aspects of language that would not require maximal discreteness in phonological features. I will suggest that these studies do not adequately account for prosodic features that would not require anatomical changes in early hominins when considering protolanguage, as they are based on a fundamentally modern view of modern languages which place a heavier load on phonological features at the cost of prosodic load. Therefore, a reanalysis of anatomical changes in early hominins is necessary.

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A Reanalysis of Anatomical Changes for Language

  1. 1. A Reanalysis of Anatomical Changes for Language<br />Richard Littauer<br />University of Edinburgh<br />richard.littauer@gmail.com<br />@richLitt<br />
  2. 2. Outline<br />Anatomical evolution driven by speech<br />
  3. 3. Outline<br />Anatomical evolution driven by speech<br />Descent of the larynx<br />
  4. 4. Outline<br />Anatomical evolution driven by speech<br />Descent of the larynx<br />Loss of laryngeal air sacs and the hyoid bone<br />
  5. 5. Outline<br />Anatomical evolution driven by speech<br />Descent of the larynx<br />Loss of laryngeal air sacs and the hyoid bone<br />Other reasons<br />
  6. 6. Outline<br />Anatomical evolution driven by speech<br />Descent of the larynx<br />Loss of laryngeal air sacs and the hyoid bone<br />Other reasons<br />Phonological realisation in whistle languages<br />
  7. 7. Outline<br />Anatomical evolution driven by speech<br />Descent of the larynx<br />Loss of laryngeal air sacs and the hyoid bone<br />Other reasons<br />Phonological realisation in whistle languages<br />Conclusion<br />
  8. 8. Evolution of Homo sapiens<br />15mya – Hominidae(from gibbons)<br />
  9. 9. Evolution of Homo sapiens<br />15mya – Hominidae(from gibbons)<br />10mya – Hominini(from gorilla)<br />
  10. 10. Evolution of Homo sapiens<br />15mya – Hominidae(from gibbons)<br />10mya – Hominini(from gorilla)<br />4.6mya – Ardipithicus(arboreal)<br />
  11. 11. Evolution of Homo sapiens<br />15mya – Hominidae(from gibbons)<br />10mya – Hominini(from gorilla)<br />4.6mya – Ardipithicus(arboreal)<br />3.3mya – Austrolopithecusafarensis (bipedal)<br />
  12. 12. Evolution of Homo sapiens<br />15mya – Hominidae(from gibbons)<br />10mya – Hominini(from gorilla)<br />4.6mya – Ardipithicus(arboreal)<br />3.3mya – Austrolopithecusafarensis (bipedal)<br />1.2mya – Homo neanderthalensis<br />
  13. 13. Evolution of Homo sapiens<br />15mya – Hominidae(from gibbons)<br />10mya – Hominini(from gorilla)<br />4.6mya – Ardipithicus(arboreal)<br />3.3mya – Austrolopithecusafarensis (bipedal)<br />1.2mya – Homo neanderthalensis<br />600kya – Homo heidelbergensis<br />
  14. 14. Evolution of Homo sapiens<br />15mya – Hominidae(from gibbons)<br />10mya – Hominini(from gorilla)<br />4.6mya – Ardipithicus(arboreal)<br />3.3mya – Austrolopithecusafarensis (bipedal)<br />1.2mya – Homo neanderthalensis<br />600kya – Homo heidelbergensis<br />200kya – Homo sapiens<br />
  15. 15. Descent of the Larynx<br />Leibermanet al. (1969) – for speech<br />
  16. 16. Descent of the Larynx <br />However, Fitch (1994) argued otherwise:<br />
  17. 17. Descent of the Larynx <br />However, Fitch (1994) argued otherwise:<br />Two reasons for descent of the human larynx:<br />
  18. 18. Descent of the Larynx <br />However, Fitch (1994) argued otherwise:<br />Two reasons for descent of the human larynx:<br /> Early, for size exaggeration<br />
  19. 19. Descent of the Larynx <br />However, Fitch (1994) argued otherwise:<br />Two reasons for descent of the human larynx:<br /> Early, for size exaggeration<br /> Later, giving 2-chamber vocal tract<br />
  20. 20. Descent of the Larynx <br />However, Fitch (1994) argued otherwise:<br />Two reasons for descent of the human larynx:<br /> Early, for size exaggeration<br /> Later, giving 2-chamber vocal tract<br />“Improved speech is no longer the only plausible evolutionary explanation for laryngeal descent, as previously assumed (Lieberman 1984), and it is possible that the descended larynx in adults evolved before spoken language.” Fitch (2009, 293)<br />
  21. 21. Descent of the Larynx<br />What does this mean? <br />
  22. 22. Descent of the Larynx<br />What does this mean?<br />That the evolutionary timeline is loose.<br />
  23. 23. Descent of the Larynx<br />What does this mean?<br />That the evolutionary timeline is loose.<br />Case and point; the hyoid bone.<br />
  24. 24. Descent of the Larynx<br />What does this mean?<br />That the evolutionary timeline is loose.<br />Case and point; the hyoid bone.<br />Specimens from A. afarensisand H. heidelbergensis<br />
  25. 25. Laryngeal Air Sacs<br />Air sacs are cavities that are attached to the vocal apparatus. They are present in many mammals (Frey et al., 2007). <br />
  26. 26. Laryngeal Air Sacs<br />Air sacs are cavities that are attached to the vocal apparatus. They are present in many mammals (Frey et al., 2007). <br />Only lateral ventricle air sacs occur in the ape line (Hewitt et al., 2002). <br />
  27. 27. Laryngeal Air Sacs<br />Air sacs are cavities that are attached to the vocal apparatus. They are present in many mammals (Frey et al., 2007). <br />Only lateral ventricle air sacs occur in the ape line (Hewitt et al., 2002). <br />Homo sapiens no longer have air sacs, except in rare pathological cases and in certain specific circumstances involving irregular behavior-caused modification of the vocal tract.<br />
  28. 28. Laryngeal Air Sacs<br />
  29. 29. Laryngeal Air Sacs<br />Justifications for loss:<br />
  30. 30. Laryngeal Air Sacs<br />Justifications for loss:<br />‘Airsacculitis’: infection of the air sac. <br />
  31. 31. Laryngeal Air Sacs<br />Justifications for loss:<br />‘Airsacculitis’: infection of the air sac.<br />The ability to modify breathing patterns<br />
  32. 32. Laryngeal Air Sacs<br />Justifications for loss:<br />‘Airsacculitis’: infection of the air sac.<br />The ability to modify breathing patterns<br />Reduction of the need for a device that would prevent hyperventilating (Hewitt et al., 2002) <br />
  33. 33. Laryngeal Air Sacs<br />Justifications for loss:<br />‘Airsacculitis’: infection of the air sac.<br />The ability to modify breathing patterns<br />Reduction of the need for a device that would prevent hyperventilating (Hewitt et al., 2002)<br />Disadvantageous for subtle, timed, and distinct sounds, which are necessary for human speech. (de Boer 2010) <br />
  34. 34. Laryngeal Air Sacs<br />Two arguments for recent loss (less than 600kya):<br />
  35. 35. Laryngeal Air Sacs<br />Two arguments for recent loss (less than 600kya):<br />Anatomical herniation<br />
  36. 36. Laryngeal Air Sacs<br />Two arguments for recent loss (less than 600kya):<br />Anatomical herniation<br />Size/Loss correlation<br />
  37. 37. Laryngeal Air Sacs<br />Anatomical evidence for the hyoid bone and the bulla as the sole indicators of air sacs is poor.<br />
  38. 38. Laryngeal Air Sacs<br />Anatomical evidence for the hyoid bone and the bulla as the sole indicators of air sacs is poor.<br />Laryngeal air sacs can regularly project between, reposition, and herniate muscles in the larynx (Giovannielloet al., 1970)<br />
  39. 39. Laryngeal Air Sacs<br />Anatomical evidence for the hyoid bone and the bulla as the sole indicators of air sacs is poor.<br />Laryngeal air sacs can regularly project between, reposition, and herniate muscles in the larynx (Giovannielloet al., 1970)<br />In primates, “A maximum of four types of [laryngeal] air sac (lateral ventricular, subhyoid, infraglottal and dorsal) have been identified, but no single source describes the morphology and summarises the distribution of all the types of air sac.” (Hewitt et al., 2002; 71) <br />
  40. 40. Laryngeal Air Sacs<br />Anatomical evidence for the hyoid bone and the bulla as the sole indicators of air sacs is poor.<br />Laryngeal air sacs can regularly project between, reposition, and herniate muscles in the larynx (Giovannielloet al., 1970)<br />In primates, “A maximum of four types of [laryngeal] air sac (lateral ventricular, subhyoid, infraglottal and dorsal) have been identified, but no single source describes the morphology and summarises the distribution of all the types of air sac.” (Hewitt et al., 2002; 71) <br />Laryngocoeles can occur due to excessive build up in pressure in the glottis, which stretches the internal wall to form a sac. <br />
  41. 41. Laryngeal Air Sacs<br />In 75% of studies involving air sac loss in primates, they were lost coincidentally with size reduction. (Hewitt et al. 2002)<br />
  42. 42. Laryngeal Air Sacs<br />In 75% of studies involving air sac loss in primates, they were lost coincidentally with size reduction. (Hewitt et al. 2002)<br />This was a synchronic study, and so Homo sapiens was considered an exception<br />
  43. 43. Laryngeal Air Sacs<br />In 75% of studies involving air sac loss in primates, they were lost coincidentally with size reduction. (Hewitt et al. 2002)<br />This was a synchronic study, and so Homo sapiens was considered an exception<br />But – Homo heidelbergensiswas taller and more robust than Homo sapiens. (Churchhillet al. 2000)<br />
  44. 44. Laryngeal Air Sacs<br />Two justifications for loss itself:<br />
  45. 45. Laryngeal Air Sacs<br />Two justifications for loss itself:<br />Call directionality<br />
  46. 46. Laryngeal Air Sacs<br />Two justifications for loss itself:<br />Call directionality<br />Regular breathing<br />
  47. 47. Laryngeal Air Sacs<br />Call directionality:<br />
  48. 48. Laryngeal Air Sacs<br />Call directionality:<br />The linguistic niche of hunting in the environment in which early hominin hunters (1.2mya) have been posited to exist is the savannah.<br />
  49. 49. Laryngeal Air Sacs<br />Call directionality:<br />The linguistic niche of hunting in the environment in which early hominin hunters (1.2mya) have been posited to exist is the savannah.<br />This would have been better suited to higher frequency, directional calls as opposed to lower frequency, multidirectional calls.<br />
  50. 50. Laryngeal Air Sacs<br />Call directionality:<br />The loss of air sacs would have then been directly advantageous, as lower frequencies produced by air sac vocalisations over bare ground have been shown to favor multidirectional over targeted utterances (Frey and Gebler, 2003; 469). <br />
  51. 51. Laryngeal Air Sacs<br />Regulated Breathing:<br />
  52. 52. Laryngeal Air Sacs<br />Regulated Breathing:<br />Laryngeal ventricular air sacs, as seen in apes, open into the vocal tract above the vocal folds. <br />
  53. 53. Laryngeal Air Sacs<br />Regulated Breathing:<br />Laryngeal ventricular air sacs, as seen in apes, open into the vocal tract above the vocal folds.<br />This means that, as air is passed into the lungs, air is drawn from the sac, and as it is exhaled, the sac fills with air. <br />
  54. 54. Laryngeal Air Sacs<br />Regulated Breathing:<br />Laryngeal ventricular air sacs, as seen in apes, open into the vocal tract above the vocal folds.<br />This means that, as air is passed into the lungs, air is drawn from the sac, and as it is exhaled, the sac fills with air. <br />The air sac would serve as a sink of already-used air that would continually be reused while breathing, an inefficient mechanism that would be disadvantageous in cases of sustained oxygen depletion.<br />
  55. 55. Laryngeal Air Sacs<br />The point being?<br />
  56. 56. Laryngeal Air Sacs<br />The point being?<br />There are paralinguistic reasons for loss of air sacs, as well. Claims otherwise are speculative. <br />
  57. 57. Other Anatomical Changes<br />Other anatomical changes for speech:<br />
  58. 58. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal<br />
  59. 59. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />
  60. 60. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control<br />
  61. 61. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control (1.2–100kya: McLarnon and Hewitt 1999)<br />
  62. 62. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control (1.2–100kya: McLarnon and Hewitt 1999)<br />Specialisedhearing<br />
  63. 63. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control (1.2–100kya: McLarnon and Hewitt 1999)<br />Specialised hearing (Related to what you produce: Hauser and Anderson 1994)<br />
  64. 64. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control (1.2–100kya: McLarnon and Hewitt 1999)<br />Specialised hearing (Related to what you produce: Hauser and Anderson 1994)<br />Mirror neurons<br />
  65. 65. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control (1.2–100kya: McLarnon and Hewitt 1999)<br />Specialised hearing (Related to what you produce: Hauser and Anderson 1994)<br />Mirror neurons (As far back as Pan)<br />
  66. 66. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control (1.2–100kya: McLarnon and Hewitt 1999)<br />Specialised hearing (Related to what you produce: Hauser and Anderson 1994)<br />Mirror neurons (As far back as Pan)<br />FOX2P<br />
  67. 67. Other Anatomical Changes<br />Other anatomical changes for speech:<br />Hypoglossal canal (debunked: DeGustaet al. 1999)<br />Voluntary breathing control (1.2–100kya: McLarnon and Hewitt 1999)<br />Specialised hearing (Related to what you produce: Hauser and Anderson 1994)<br />Mirror neurons (As far back as Pan)<br />FOX2P (In mice and orangutans.)<br />
  68. 68. Other Anatomical Changes<br />So, what remains?<br />
  69. 69. Other Anatomical Changes<br />So, what remains?<br />The conclusion that there are no major specific anatomical changes that can be traced irrefutably to language. <br />
  70. 70. Phonological Implications<br />Current theoretical studies on the evolution of sounds depend almost entirely on complex phonemic inventories<br />
  71. 71. Phonological Implications<br />Current theoretical studies on the evolution of sounds depend almost entirely on complex phonemic inventories<br />These do not exist a priori, but rather appear through cultural evolutionary processes<br />
  72. 72. Phonological Implications<br />Current theoretical studies on the evolution of sounds depend almost entirely on complex phonemic inventories<br />These do not exist a priori, but rather appear through cultural evolutionary processes<br />Self-organisation<br />
  73. 73. Phonological Implications<br />Current theoretical studies on the evolution of sounds depend almost entirely on complex phonemic inventories<br />These do not exist a priori, but rather appear through cultural evolutionary processes<br />Self-organisation<br />Phenomena of the third kind (Invisible hand)<br />
  74. 74. Phonological Implications<br />Most current theoretical studies on the evolution of sounds depend almost entirely on complex phonemic inventories<br />These do not exist a priori, but rather appear through cultural evolutionary processes<br />Self-organisation<br />Phenomena of the third kind (Invisible hand)<br />With bounded constraints (production, perception)<br />
  75. 75. Phonological Implications<br />However, they take it for a given that these sounds shaped anatomy, rather than are artefacts of it.<br />
  76. 76. Phonological Implications<br />However, they take it for a given that these sounds shaped anatomy, rather than are artefacts of it.<br />“The investigation of the interaction between vocal fold interactions and vocal tracts with air sacs presented here, although preliminary and incomplete, supports the hypothesis that the evolutionary disappearance of air sacs is related to the emergence of complex vocal communication.” (de Boer, 2010)<br />
  77. 77. Phonological Implications<br />If complex phonemic inventories did not shape their anatomical mechanisms of production (as I’ve suggested), then other modes of communication may be equally weighted in protolanguage theories<br />
  78. 78. Phonological Implications<br />If complex phonemic inventories did not shape their anatomical mechanisms of production (as I’ve suggested), then other modes of communication may be equally weighted in protolanguage theories<br />These would include:<br />
  79. 79. Phonological Implications<br />If complex phonemic inventories did not shape their anatomical mechanisms of production (as I’ve suggested), then other modes of communication may be equally weighted in protolanguage theories<br />These would include:<br />Whistled/hummed language<br />
  80. 80. Phonological Implications<br />If complex phonemic inventories did not shape their anatomical mechanisms of production (as I’ve suggested), then other modes of communication may be equally weighted in protolanguage theories<br />These would include:<br />Whistled/hummed language<br />Gesture and signed language<br />
  81. 81. Phonological Implications<br />If complex phonemic inventories did not shape their anatomical mechanisms of production (as I’ve suggested), then other modes of communication may be equally weighted in protolanguage theories<br />These would include:<br />Whistled/hummed language<br />Gesture and signed language<br />Non-arbitrary phonemic language<br />
  82. 82. Phonological Implications<br />Whistled languages:<br />
  83. 83. Phonological Implications<br />Whistled languages:<br />Copy the tone, formants, intonation of regular language<br />
  84. 84. Phonological Implications<br />Whistled languages: (Meyer 2008)<br />Copy the tone, formants, intonation of regular language<br />Are more common and more unimodal in tonal languages<br />
  85. 85. Phonological Implications<br />Whistled languages: (Meyer 2008)<br />Copy the tone, formants, intonation of regular language<br />Are more common and more unimodal in tonal languages<br />Suitable for different environments (as clicks are (Knight et al. 2003)<br />
  86. 86. Phonological Implications<br />Whistled languages: (Meyer 2008)<br />Copy the tone, formants, intonation of regular language<br />Are more common and more unimodal in tonal languages<br />Suitable for different environments (as clicks are (Knight et al. 2003)<br />Interchangeable with regular language<br />
  87. 87. Phonological Implications<br />Non-arbitrariness in language: (Cuskley 2008)<br />
  88. 88. Phonological Implications<br />Non-arbitrariness in language: (Cuskley 2008)<br />Iconicity<br />
  89. 89. Phonological Implications<br />Non-arbitrariness in language: (Cuskley 2008)<br />Iconicity<br />Phonesthemes<br />
  90. 90. Phonological Implications<br />Non-arbitrariness in language: (Cuskley 2008)<br />Iconicity<br />Phonesthemes<br />Infant directed speech<br />
  91. 91. Phonological Implications<br />Non-arbitrariness in language: (Cuskley 2008)<br />Ideophones (Voeltz & Killian-Hatz, 2001)<br />Phonesthemes (Bergen, 2001)<br />Infant directed speech (Nygaard et al, 2009)<br />Statistical correspondences (Tamariz, 2005)<br />
  92. 92. Conclusion<br />To sum up:<br />
  93. 93. Conclusion<br />To sum up:<br />The major reasons cited for the evolution of speech mechanisms are somewhat unsubstantiated<br />
  94. 94. Conclusion<br />To sum up:<br />The major reasons cited for the evolution of speech mechanisms are somewhat unsubstantiated<br />This results in a re-appraisal of language evolution to a more recent time period – or suggests that different language-internal pressures were present in protolanguage<br />
  95. 95. Conclusion<br />To sum up:<br />Multimodality is an integral part of otherwise solely-phonological speech<br />
  96. 96. Conclusion<br />To sum up:<br />Multimodality is an integral part of otherwise solely-phonological speech<br />Given this, reducing justifications for anatomical change to phonemic systems is unjustified, and a reanalysis of evolutionary phonology is warranted. <br />
  97. 97. Conclusion<br />Thank you.<br />References available upon request.<br />

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