3.1 The study of sound systems and patterns
3.2 Phonemes and allophone
Allophone: The different phones which can represent a phoneme in different phonetic environment are called the allophone of that phone.
3.3 Discovering phonemes
The phonetic context (what sound precedes and what sound follows) in which a sound appears in soeech is called its environment.
3.3.1 Contrastive distribution
If sounds appear in the same environment and distinguish meaning, they are said to be in contrastive distribution.
3.3.2 Complementary distribution
3.3.3 Free variation
If segments appear in the same position but the mutual substitution does not result in change of meaning, they are said to be in free variation.
3.8 Suprasegmental features
features that are found over a segment or a sequence of two or more segment, which are called suprasegmental features.
STRESS
is defined as the perceived prominence (comparative loudness) of one or more syllabic elements over others in a word or a sentence
intensity, pitch, variation, vowel duration and vowel quality
3.7 Sequence of phonemes
These resrtictions on sequence of phonemes are known as phonotactic constrains.
The longest coda in English may contain four sonsonants
Sequences that are possible but do not occur yet are called accidental gaps
3.6 Syllable structure
A syllable : is a phonological unit that is composed of one or more phonemes
3.5 Phonological rules
(i) Devoice a voiced consonant after a voiceless consonant在一个轻辅音后把发音辅音不发音例：play pray
【+voiced+consonantal]---[-voiced]/[-voiced +consonant]_
(ii) Nasalize vowels before nasals
(iii) An alvelar stop becomes a flap when preceded by a stressed vowel and followed by an unstressed vowel
(iiii) Voiceless stops are aspirated when they occur initially in a stressed syllable
3.4 Distinctive features and non-distinctive features
Features that distinguish meaning are called distinctive features, and feature that do not, non-distinctive features.
phone是音素 phoneme 是音位学基本单位 语音学基本单位是音段
