教师解析：

I. Phonology

1. Definition of phonology

Phonology is the study of sound systems and patterns. Phonology and phonetics are two studies different in perspectives, which are concerned with the study of speech sounds. •

2. Phonology focuses on three fundamental questions

• What sounds make up the list of sounds that can distinguish meaning in a particular language?

• What sounds vary in what ways in what context?

• What sounds can appear together in a sequence in a particular language?

3. Differences between phonetics and phonology

Phonetics is the study of speech sounds. Phonology is the study of sound systems and patterns.

Phonetics and phonology are both concerned with the study of speech sounds, but they two differ in perspectives. Phonetics, particularly articulatory phonetics, focuses on how speech sounds are produced, what phonetic features they have, and how to transcribe them. In phonetics, sound segments are assumed to be invariable; variations are overlooked. Phonology focuses on the following three fundamental questions: What sounds make up the list of sounds that can distinguish meaning in a particular language? What sounds make up the list of ways in what context? What sounds can appear together in a sequence in a particular language?

II. Phonemes and allophones

A phoneme is a distinctive, abstract sound unit with a distinctive feature. •

The one in lead is clear, [l], the one in deal is dark [l], and the one in slight is voiceless [l]. These variants of a phoneme are termed allophones. We use allophones to realize phonemes.