Speech Sounds and Articulation

Speech Sound Production

Introduction

• This mini-lecture discusses the production of speech sounds by the body and mind.
• Speech sounds relate to the physical properties of sound, transitioning from auditory cognition to language.

Production of Speech Sounds

• Acoustic signal of speech is produced by pushing air out through the lungs and vocal cords.
• Vocal cords may or may not be vibrating.
  • Most of the time when talking, vocal cords are vibrating.
  • Whispering involves the same sounds but without vocal cord vibration.
• Air is pushed out of the lungs through the vocal cords and vocal tract.

Vocal Tract and Articulators

• The vocal tract includes several articulators:
  • Tongue
  • Teeth
  • Lips
  • Alveolar ridge
  • Nasal cavity
  • Hard palate
  • Soft palate
  • Pharynx
• These anatomical structures in the mouths and noses shape speech sounds.
• The tongue is the most important articulator, but other parts of the mouth and nose are also important.
• Articulators are the parts of the vocal tract that can be moved to make speech sounds.

Examples of Articulator Movements

• Bringing lips together interrupts airflow (e.g., "p" sound).
• The alveolar ridge is the roof of the mouth behind the teeth.
  • Important for producing sounds in English.
• The soft palate is the movable part of the roof of the mouth.
  • Pushing the back of the tongue against the soft palate produces sounds like "g".
• Different sounds involve moving articulators while producing a stream of air.

MRI Video of Articulator Movements

• An MRI video demonstrates the movement of the tongue, lips, and soft palate during speech.
• The video shows how these articulators move around within the mouth as a person talks.

Vowels vs. Consonants

• The distinction between vowels and consonants is based on the obstruction of air as it leaves the lungs.
  • Consonants involve obstruction of air.
  • Vowels involve little to no obstruction.

Vowels

• Different vowels are created by changing the shape of the vocal tract.
• This changes the resonant frequency of the vocal tract and the pitch of the resulting sound.
• The tongue does most of the work, but the shape of the lips also matters.
• Examples of vowel sounds: ah, a, e, ah, u.

Articulator Movements for Vowel Sounds

• /ɑ/ (as in "father"):
  • The tongue moves around a lot.
  • The lips are open.
• /i/ (as in "eat"):
  • The tongue is high up in the mouth.
  • The lips are slightly open.
  • The back of the mouth is obstructed by the tongue.
• /oʊ/ (as in "boat"):
  • The tongue is up in the mouth, causing obstruction.
  • The lips are pursed.

Characteristics of Vowels

• Vowels are differentiated by:
  • Closeness of the tongue to the floor of the mouth.
  • Backness of the tongue in the mouth.
  • Degree of rounding of the lips.
• These characteristics can be organized in a two-dimensional schematic diagram.
  • Front vs. back vowels.
  • Closed vs. open vowels.
• Front vowels are typically unrounded, and back vowels are typically rounded in English, but this varies in other languages.

Examples of Vowel Characteristics

• /ɑ/ (as in "father") is back, open, and unrounded.
• /æ/ (as in "at") is front, open, and unrounded.
• /i/ (as in "eat") is front, close, and unrounded.
• /ɔ/ (as in "caught") is back, open, and rounded.
• /oʊ/ (as in "boat") is back, closed, and rounded.

Consonants: Manner and Place of Articulation

• Consonants involve partial or full obstruction of airflow through the mouth.
• Differentiated by:
  • Manner of articulation: How articulators disrupt airflow.
  • Place of articulation: Where articulators come together.
  • Voicing: Whether vocal cords vibrate (voiced) or not (voiceless).
• During voiced consonants, vocal cords vibrate as air is forced through the vocal tract; during voiceless consonants, they do not.