Phonetics and Phonology: Distinctive Features and Vowel Sounds

Distinctive Feature Theory

Distinctive Feature Theory challenges Phoneme Theory (PT) by focusing on the features that compose phonemes, rather than the phonemes themselves. This approach questions the validity of the phoneme concept, arguing that speech is not simply a series of discrete sounds.

Natural Class: A set of sounds sharing phonetic features, affected by the same environment, and having the same effect on surrounding sounds.

Major Class Features

• Vowels: [+SYLLABIC], [+SONORANT], [-CONSONANTAL] - form the syllable nucleus.
• Glides: [-SYLLABIC], [+SONORANT], [-CONSONANTAL].
• Sonorant Consonants (nasals and liquids): [+/-SYLLABIC], [+SONORANT], [+CONSONANTAL].
• Obstruents: [-SYLLABIC], [-SONORANT], [+CONSONANTAL].

Consonant Features

• Voice: [+/-VOICE] - vocal fold vibration.
• Manner: [+/-NASAL], [+/-CONTINUANT], [+/-STRIDENT], [+/-LATERAL], [+/-DELAYED RELEASE].

Weak Forms: Involve weakening or loss of a vowel or consonant, often due to stress, also known as gradation or apophony.

VOT (Voice Onset Time): The acoustic difference between voiceless aspirated and unaspirated stops.

Vowels vs. Consonants

Vowels are produced with unobstructed airflow, form the syllable nucleus, are typically voiced, and are more audible. Consonants involve obstructed airflow, are marginal in syllables, can be voiced or unvoiced, and are less audible but more vital for understanding.

English Vowel Sounds

• /iː/: Front, close, unrounded (often diphthongized to [ij]).
• /ɪ/: Front, close-mid, unrounded (used in endings like -ace, -age, -ate, -ness).
• /e/: Front, mid, unrounded.
• /æ/: Front, open-mid, unrounded.
• /ɑː/: Back, open, unrounded (often before unvoiced fricatives f, θ, s or voiced fricative ð plus vowel).
• /ɒ/: Back, open, rounded.
• /ɔː/: Back, mid, rounded.
• /ʊ/: Back-central, close-mid, rounded.
• /uː/: Back, close, rounded.
• /ʌ/: Central, open-mid, unrounded.
• /ɜː/: Central, mid, unrounded.
• /ə/: Central, mid, unrounded.

Distinctive Features Summary

Major Class Features

• Vowels: [+syll, +son, -cons]
• Glides: [-syll, +son, -cons]
• Sonorant Consonants: [+/-syll, +son, +cons]
• Obstruents: [-syll, -son, +cons]

Place of Articulation

• Labials: [+ant, -cor] (p, b, m)
• Dentals/Alveolars: [+ant, +cor] (t, d, n)
• Palato-alveolars/Palatals: [-ant, +cor]
• Velars/Glottals: [-ant, -cor] (k, g, ŋ)