CS626-449: Speech, NLP and the Web/Topics in AI

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CS626-449 Speech, NLP and the Web/Topics in AI

• Pushpak Bhattacharyya
• CSE Dept., IIT Bombay
• Lecture-23 Phonetics contd.
• (lecture 21, 22 taken by Anup on Graphical Models)

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Phonteic Symbols and IPA notation
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IPA vowels
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Need for Phonetic Transcription

• Not every language has a writing system
• Not every writing system represents sounds
  (Chinese characters)
• Not every sound-representing writing system
  represents segments (Japanese hiragana and
  katakana)
• The representation of speech sounds in
  segment-representing writing systems is
  problematic because it is highly inconsistent
  (English)

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Sound to Symbol relationship is arbitrary

• One letter, one sound b represents b in ball,
  breathe, cab
• A set of letters, one sound architect, shampoo,
  teeth, though, cheese, enough
• One letter, many sounds a represents æ in cat,
  ej in cave, ? in car, ? in alike
• One sound, many letters i represented
  differently in sea, see, he, key, believe,
  receive, people, machine
• One letter, no sound knight (cf. night) , write
  (cf. right, rite), comb

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Vocal Organs
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(No Transcript)
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Classification

• Manner of articulation
• Place of articulation
• Voicedness

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The sound producing system

• Lungs the source of air
• Larynx the source of noise/sound
• Vocal cords/folds
• Glottis
• Vocal tract the source of resonance/ the filters
  
• Pharynx
• Oral cavity
• Nasal cavity

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Articulation of consonants Larynx action/glottis
state

• Vocal cords are pulled apart. The air passes
  freely through the glottis. This is called the
  voicelessness state and sounds produced with this
  configuration of the vocal cords are called
  voiceless p t k f ? s ? t?
• Vocal cords are pulled close together. The air
  passing through the glottis causes the vocal
  cords to vibrate. This is called the voicing
  state and sounds produced with this configuration
  of the vocal cords are called voiced b d g v ð z
  ? d?
• Vocal cords are apart at the back and pulled
  together at the front. This is called the whisper
  state.
• Vocal cords assume the voicing state but are
  relaxed. This is called the murmur state.

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Place of Articulation (1/2)

• Labial closure or near-closure of the lips
• bilabial p b m
• labiodental f v
• Dental tip of the tongue against upper teeth or
  between them
• interdental ? ð
• Alveolar tongue against or near alveolar ridge
• t d s z n l r
• Alveopalatal body of tongue on or near area
  behind alveolar ridge
• ? ? t? d?
• Palatal body of the tongue on or near the palate
  
• j

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Place of articulation (2/2)

• velar back of the tongue touching or near the
  velum
• k g ?
• Uvular tongue touching or near the uvula
• Pharyngeal retraction of the tongue or
  constriction of pharynx
• glottal vocal folds as primary articulation h ?