Phonetic Classification and the Mechanics of Human Hearing

Acoustic and Articulatory Classification of Speech Sounds

Places of Articulation (Phonetic Classification)

Sounds are classified based on where the vocal tract is constricted:

• Labial (Lip): Severe and diffuse sound, articulated with the lips.
  • Voiced (Sonoro): (b, m)
  • Unvoiced (Sordo): (p, f)
• Dental: Acute and diffuse sound, articulated with the tongue on the teeth (anterior and coronal).
  • Voiced (Sonoro): (d)
  • Unvoiced (Sordo): (t, s [strident], c [mate])
• Velar (Soft Palate): Serious, thick sound, articulated by striking the tongue against the soft palate (velum).
  • Voiced (Sonoro): (g [as in 'gue'])
  • Unvoiced (Sordo): (k, x [j])
• Palatal: Acute and dense sound, articulated by rubbing the tongue against the hard palate (coronal).
  • Voiced (Sonoro): (ñ, y)
  • Unvoiced (Sordo): (ch)
• Alveolar: Acute and diffuse sound, articulated by scraping the tongue against the alveolar ridge (coronal).
  • Voiced (Sonoro): (d, n, l, r, rr)
  • Unvoiced (Sordo): (s [strident], c [mate], t)

Summary of Sound Examples by Place

• Labials: m, b, p, f
• Alveolar and Dental: l, r, rr, n, d, t, s, c
• Palatals: ñ, ch
• Velars: k, j, g (as in 'gue')

Manner of Articulation and Acoustic Features

Sounds are further categorized by how airflow is managed:

• Interrupt (Stops/Plosives): Correspond to a true silence, closing the vocal tract completely.
• Continuous (Fricatives/Continuants): Narrow the duct, creating air friction.

Acoustic Classification by Frequency and Duration

• Grave Continuous: m, b, f, g (gue)
• Grave Interrupt: p, k
• Acute Continuous: n, ñ, l, ll, d, y
• Acute Interrupt: t, ch, s

Duration and Tension

• Tense: Long duration.
• Light: Short duration.
• R/L Distinction: The sound r is diffuse, while l is sharp (acute).
• Rhotics:
  • Interrupt: l
  • Continuous and Tense: rr
  • Continuous and Weak: r

Sibilant Characteristics

• Strident: Articulated with rough edges (e.g., the northern /s/).
• Matt: Articulated with smooth edges (e.g., the southern dorsal dental /c/ or /s/).

Fundamentals of Sound Perception and Auditory Anatomy

Harmonics and Formants

The harmonics are what generate the distinctive timbre of a sound source, allowing us to differentiate instruments or recognize a person's voice. The formants are the harmonics that are maximally enhanced.

Components of the Human Ear

1. Tympanic Membrane (Eardrum): It moves as a result of air vibrations coming through the outer ear canal. The movements are transmitted to the inner ear via the middle ear bones.
2. Ossicular Chain: Transmits the movement of the eardrum to the inner ear through the oval window.
3. Eustachian Tube: Equalizes pressure on both sides of the eardrum.
4. Cochlea (Bony Labyrinth): Contains the organ of Corti, which is the sensory organ of hearing and transmits sound information to the brain.
5. Basilar Membrane: Located inside the cochlea, it is responsible for the frequency response of human hearing.
6. Auditory Nerve: Responsible for balance and hearing function. The cochlear nerve component carries information specifically about sound.