Articulatory Phonetics
Articulatory phonetics is about how we physically produce speech sounds. It classifies sounds based on what your mouth, tongue, and vocal tract are doing during production. Understanding these classifications gives you a systematic way to describe any speech sound in any language.
Vowels vs. Consonants
The most basic division in speech sounds is between vowels and consonants, and the difference comes down to airflow.
- Vowels are produced with a relatively open vocal tract, so air flows through without major obstruction. They're almost always voiced (your vocal folds vibrate). The English letters a, e, i, o, u represent vowels, though the actual number of vowel sounds in English is much larger.
- Consonants are produced by obstructing airflow somewhere in the vocal tract. That obstruction can be complete (like blocking air with your lips for [p]) or partial (like narrowing the gap for [s]). Consonants can be either voiced or voiceless.
On a spectrogram (a visual representation of sound), vowels show up as dark horizontal bands called formants, which reflect the resonant frequencies of the vocal tract. Consonants look quite different: voiceless consonants appear as bursts of noise or silence, while voiced consonants show some periodic vibration.
Classification of Consonants
Every consonant can be described using three features. Think of it as a three-part address for any consonant sound.
1. Voicing: Are the vocal folds vibrating?
- Voiced sounds involve vibration ([b], [d], [g]). Put your fingers on your throat and say "zzz" to feel it.
- Voiceless sounds have no vibration ([p], [t], [k]). Try "sss" and notice the difference.
2. Place of articulation: Where in the vocal tract is the obstruction?
- Bilabial — both lips ([p], [b], [m])
- Labiodental — lower lip + upper teeth ([f], [v])
- Dental — tongue tip + teeth ([θ] as in think, [ð] as in this)
- Alveolar — tongue tip + alveolar ridge ([t], [d], [s], [n])
- Postalveolar — tongue + area just behind the alveolar ridge ([ʃ] as in ship, [ʒ] as in measure)
- Palatal — tongue body + hard palate ([j] as in yes)
- Velar — tongue back + soft palate ([k], [g], [ŋ] as in sing)
- Glottal — at the vocal folds ([h], [ʔ] as in the catch in uh-oh)
Other places (retroflex, uvular, pharyngeal) exist across the world's languages but aren't used in standard English.
3. Manner of articulation: How is the airflow modified?
- Stops (plosives) — airflow is completely blocked, then released ([p], [t], [k])
- Fricatives — airflow is narrowed, creating turbulent noise ([f], [s], [ʃ])
- Affricates — a stop followed immediately by a fricative ([tʃ] as in church, [dʒ] as in judge)
- Nasals — air is blocked in the mouth but flows through the nose ([m], [n], [ŋ])
- Approximants — articulators come close but don't create friction ([w], [ɹ], [j])
- Laterals — air flows around the sides of the tongue ([l])
So a full consonant description sounds like: [t] is a voiceless alveolar stop, and [v] is a voiced labiodental fricative.
Classification of Vowels
Vowels are classified by what your tongue and lips are doing. Since there's no point of obstruction to reference, linguists describe vowels using three parameters:
1. Tongue height — How high or low is the tongue?
- High (or close): [i] as in see, [u] as in boot
- Mid: [e] as in say, [o] as in go
- Low (or open): [a] as in father
2. Tongue advancement — Is the tongue pushed forward or pulled back?
- Front: [i], [e] (tongue is forward in the mouth)
- Central: [ə] as in the unstressed vowel in sofa
- Back: [u], [o] (tongue is pulled toward the back)
3. Lip rounding — Are the lips rounded or spread?
- Rounded: [u], [o] (lips form a circle)
- Unrounded: [i], [e], [a] (lips are spread or neutral)
The vowel chart (or vowel trapezoid) maps these positions visually. It's shaped to roughly mirror the inside of the mouth: front vowels on the left, back vowels on the right, high vowels at the top, low vowels at the bottom. The IPA cardinal vowels serve as fixed reference points on this chart, so linguists can describe vowels consistently across languages.
Advanced Phonetic Concepts
Non-Pulmonic Consonants
Most speech sounds use a pulmonic egressive airstream, meaning air is pushed out from the lungs. But some consonants use different airstream mechanisms entirely.
- Clicks use an ingressive velaric airstream. You create a pocket of air between two closures in the mouth, rarefy it by pulling the tongue down, then release. The "tsk tsk" sound of disapproval is actually a dental click. Clicks function as regular consonants in several southern African languages like Zulu and Xhosa, with types including bilabial, dental, alveolar, lateral, and palatal clicks.
- Implosives use a glottalic ingressive airstream. The larynx moves downward while the glottis is loosely closed, pulling air inward. They sound like "swallowed" versions of voiced stops. Languages like Sindhi and Hausa use implosives at bilabial, alveolar, and palatal places of articulation.
- Ejectives use a glottalic egressive airstream. The glottis closes tightly and the larynx moves upward, compressing the air above it. When the oral closure releases, the result is a sharp, popping sound. Ejectives occur in languages like Georgian, Navajo, and many Ethiopian languages at bilabial, alveolar, and velar places.
Suprasegmental Features
Suprasegmental features operate above the level of individual segments (vowels and consonants). They span syllables, words, or entire sentences.
- Stress makes certain syllables more prominent through a combination of greater loudness, higher pitch, and longer duration. English uses lexical stress to distinguish words: REcord (noun) vs. reCORD (verb). Sentential stress highlights the most important word in a sentence, shifting meaning: SHE took the book vs. She took the BOOK.
- Tone uses pitch differences on individual syllables to change word meaning. In Mandarin Chinese, the syllable ma means "mother" with a high level tone, "hemp" with a rising tone, "horse" with a dipping tone, and "scold" with a falling tone. Other tonal languages include Thai and Yoruba.
- Intonation refers to pitch patterns across an entire phrase or sentence. Unlike tone, intonation doesn't change the dictionary meaning of a word, but it conveys information about sentence type and speaker attitude. In English, rising intonation at the end of a sentence typically signals a question (You're coming?), while falling intonation signals a statement (You're coming.).