本章节重点学习了语音学。通过本单元的学习，应该明确语音学的定义、发音机制、语音描写以及语音特征和自然分类，重点掌握英语辅音和元音描写完成课后相关练习。

Chapter 2: Phonetics: The study of speech sounds

Phonetics

 Definition: The study of speech sounds

 Sub-branches: (1) Articulatory phonetics; (2) Acoustic phonetics;

    (3) Auditory phonetics

The sound-producing mechanism

Phonetic transcription of speech sounds

 Definition of segment: Units of representation 

 Functions of IPA:

  a) It enables linguistics to transcribe speech sounds of languages consistently and

   accurately.

  b) It helps teachers and learners to distinguish the spelling and pronunciation of words.

  c) English textbooks and dictionaries generally make use of IPA in transcribing the variants

  of languages.

Description of English consonants

 Definition of consonants: Sounds produced with a narrow or complete closure in the vocal

 tract. The air stream is either blocked momentarily or obstructed partially.

 Description of consonants:

  Places of articulation: ①Bilabial; ② Labiodental; ③Interdental;

              ④Alveolar; ⑤ Palatal; ⑥Velar; ⑦Glottal.

  Manners of articulation: ①Stops; ②Fricatives; ③Affricates;

              ④Liquids; ⑤Glides; ⑥Nasals.

  Voicing of articulation: voiced and voiceless.

Description of English vowels

 Definition of vowels: Sounds made with the vocal tract more open than it is for consonants.

 There is hardly any obstruction of the airflow.

 Description of English vowels:

  What part of the tongue is raised and how high it is raised;

  Whether the jaw move and whether the tongue position is changed;

  Whether the vocal tract is constricted, i.e. whether the muscles are tense.

  Whether the lips are rounded;

Phonetic features and natural classes

 Definition of Phonetic features

 Natural classes:[+anterior], [+continuant], [+sibilant], [+syllabic] [+sonorant]

学习了这些内容后，相信大家对语音学有了更深入的了解，这将有利于大家今后的英语口语练习与学习。

如果想要了解更多关于如何学习章节的内容，请在学习资源继续了解本章拓展内容。