Phonetics
1. The differences between consonants and vowels
Consonants are produced by constricting or obstructing the vocal tract at some place to divert, impede, or completely shut off the airflow in the cavity. However, a vowel is produced without such obstruction so no turbulence or a total stopping of the air can be perceived. The distinction between vowels and consonants lies in the obstruction of airstream.
2. Manners of articulation
It refers to the actual relationship between the articulators and thus the way in which the air passes through certain part of vocal tracts. There are several basic ways in which articulation can be accomplished: the articulators may close off the oral tract for an instant or a relatively long period; they may narrow the space considerably; or they may simply modify the shape of the tract by approaching each other.
(1). Stop: complete closure of the articulators involved so that the airstream cannot escape through the mouth. It is essential to separate three phrases in the production of a stop: (a) the closing phase, in which the articulators come together; (b)the compression phrase, during which air is compressed behind the closure; (c)the release phrase, during which the articulators forming the obstruction come rapidly apart and the air is suddenly released. In English, [p, b, t, d, k, g] are stops and [m, n, ŋ] are nasals.
(2) Fricative: close approximation of two articulators so that the airstream is partially obstructed and turbulent airflow is produced. In English, [f, v, θ, ð, s, z, ʃ, ʒ, h] are fricatives.
(3)Approximant: an articulation in which one articulator is close to another, but without the vocal tract being narrowed to such an extent that a turbulent airstream is produced. The gap between the articulators is therefore larger than for a fricative and no turbulence is generated. In English, this class of sounds includes [w, r, j].
(4)Lateral: obstruction of the airstream at a pint along the center of the oral tract, with inc
omplete closure between one or both sides of the tongue and the roof of the mouth. [l] is the only lateral in English.
(5)Trill: produced when an articulator is set vibrating by the airstream. A major trill sound is [r], as in red.
(6)Affricates: involving more than one of these manners of articulation in that they consist of a stop followed immediately afterwards by a fricative at the same place of articulation. In English, the “ch [ tʃ ]” of cheese and the “j [dʒ]”of jet are both affricates.
3. Places of articulation
It refers to the point where in the vocal tract there is approximation, narrowing or the abstraction of air. Practically, consonants may be produced at any place between the tips and the vocal folds.
(1)Bilabial: made with the two lips. In English, bilabial sounds include [p, b, m, w], as in pet, bet, met and wet.
(2)Labiodental: made with the lower lip and the upper front teeth. Labiodental sounds include [f, v], as in fire and five.
(3)Dental: made by the tongue tip and the upper front teeth. Only frictives [θ, ð] are dental sounds.
(4)Alveolar: made with the tongue tip and the alveolar ridge. Sounds include [t, d, n, s, z, r, l] for English.
(5)Postalveolar: made with the tongue tip and the back of the alveolar ridge. Such sounds include [ʃ, ʒ,], as in ship and pleasure.
(6)Patatal: made with the front to the tongue and the hard palate. The only English sound made here is [j], as in yes and yet.
(7)Velar: made with the black of the tongue and the soft palate. Examples in English are velar stops [k, g], as in cat and get, and velar nasal [ŋ], as in sing.
(8)Glottal: made with the two pieces of vocal folds pushed towards each other. The only glottal is [h] in hat and head.
4. Description of the consonants (必考)
[p] voiceless bilabial stop      [b] voiced bilabial stop
[s] voiceless alveolar fricative  [z] voiced alveolar fricative
[m] bilabial nasal;            [j] palatal approximant
stops是什么音
[h] glottal fricative            [l] alveolar lateral
5. Cardinal Vowels
  The cardinal vowels are a set of vowel qualities arbitrarily defined, fixed and unchanging, intended to provide a frame of reference for the description of the actual vowels of existing languages.
6. Three types of vowels
  According to the quality of production, there are 3 types of vowels. The first one is monophthong, whose quality of production is unchangeable movement; the second one is diphthong, whose quality of production is a single change movement; and the last one is triphthong, whose quality of production is 2 change movements, such as tower /ˈtaʊə(r)/.

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