Question

What is the function of the lips in speech production?

• A. Control airflow
• B. Form bilabial sounds
• C. Open and close the glottis
• D. Modify vowel height

Answer 1

Answer:

B. Form bilabial sounds

Role of Lips in Speech Production

• Primary Function: Bilabial Sounds

  • The lips are primary articulators in the vocal tract. An articulator is any organ that moves to produce speech sounds.
  • Their main function is to form bilabial sounds, which are consonants produced by bringing both the upper and lower lips together. The term 'bilabial' literally means 'two lips' (bi- = two, labial = lips).
  • In English, the primary bilabial consonants are:
    • /p/ (as in 'pat'): a voiceless bilabial plosive. Airflow is completely stopped and then released explosively without vocal cord vibration.
    • /b/ (as in 'bat'): a voiced bilabial plosive. Similar to /p/, but with vocal cord vibration.
    • /m/ (as in 'mat'): a voiced bilabial nasal. Airflow is blocked at the lips, but escapes through the nasal cavity with vocal cord vibration.

• Other Contributions of Lips to Speech

  • Labiodental Sounds: The lower lip also interacts with the upper front teeth to produce labiodental sounds. Examples include:
    • /f/ (as in 'fan'): a voiceless labiodental fricative. Air passes through a narrow constriction between the lower lip and upper teeth.
    • /v/ (as in 'van'): a voiced labiodental fricative. Similar to /f/, but with vocal cord vibration.
  • Vowel Articulation: Lips play a crucial role in shaping the oral cavity for vowel production, influencing the sound's resonance and quality.
    • Lip Rounding/Protrusion: For vowels like /uː/ (as in 'boot') and /oʊ/ (as in 'boat'), the lips are rounded and protruded, lengthening the vocal tract.
    • Lip Spreading/Retraction: For vowels like /iː/ (as in 'feet') and /ɪ/ (as in 'sit'), the lips are spread or retracted.
  • Visual Cues: Lip movements provide essential visual information for speech perception, assisting in lip-reading (speechreading) and enhancing clarity, especially in noisy environments or for individuals with hearing impairments.

• Key Concepts in Phonetics and Phonology

  • Place of Articulation: This refers to where in the vocal tract the airflow is obstructed or constricted to form a consonant sound. Examples include bilabial, labiodental, dental, alveolar, palatal, velar, and glottal.
  • Manner of Articulation: This describes how the airflow is modified or released by the articulators (e.g., plosive, fricative, nasal, approximant, lateral).
  • Voicing: This refers to whether the vocal cords vibrate during the production of a sound (voiced) or not (voiceless).