Another example is the consonant [p]. We all know that [p] is pronounced differently in the two words pit and spit. In the word pit, the sound [p] is pronounced with a strong puff of air, but in spit the puff of air is withheld to some extent. In the case of pit, the [p] sound is said to be aspirated and in the case of spit, the [p] sound is unaspirated. This difference is not shown in broad transcription, but in narrow transcription, a small raised “h” is used to show aspiration, thus pit is transcribed as [phɪt] and spit is transcribed as [spɪt].
4. How are the English consonants classified?
答：  English consonants can be classified in two ways: one is in terms of manner of articulation and the other is in terms of place of articulation. In terms of manner of articulation the English consonants can be classified into the following types: stops, fricatives, affricates, liquids, nasals and glides. In terms of place of articulation, it can be classified into following types: bilabial, labiodental, dental, alveolar, palatal, velar and glottal.
5. What criteria are used to classify the English vowels?
答：  Vowels may be distinguished as front, central, and back according to which part of the tongue is held highest. To further distinguish members of each group, we need to apply another criterion, i.e. the openness of the mouth. Accordingly, we classify the vowels into four groups: close vowels, semi-close vowels, semi-open vowels, and open vowels. A third criterion that is often used in the classification of vowels is the shape of the lips. In English, all the front vowels and the central vowels are unfounded vowels, i. e., without rounding the lips, and all the back vowels, with the exception of [a:], are rounded. It should be noted that some front vowels can be pronounced with rounded lips.
6. A. Give the phonetic symbol for each of the following sound descriptions:
    1) voiced palatal affricate
    2) voiceless labiodental fricative
    3) voiced alveolar stop
    4) front, close, short
    5) back, semi-open, long
    6) voiceless bilabial stop
  B. Give the phonetic features of each of the following sounds:
    1) [ t ]    2) [ l ]     3) [ʧ]    4) [w]   5) [ʊ]    6) [æ]
答：A. (1) [ʤ]   (2) [ f ]   (3) [d ]   (4) [ ɪ ]  (5) [ ɔ:]  (6) [p]
    B. (1) voiceless alveolar stop           (2) voiced alveolar liquid
      (3) voiceless palatal affricate         (4) voiced bilabial glide
      (5) back, close, short               (6) front, open
7. How do phonetics and phonology differ in their focus of study? Who do you think will be more interested in the difference between, say, [l] and [ɫ], [ph] and [p], a phonetician or a phonologist? Why?
答： (1) Both phonology and phonetics are concerned with the same aspect of language –– the speech sounds. But while both are related to the study of sounds,, they differ in their approach and focus. Phonetics is of a general nature; it is interested in all the speech sounds used in all human languages: how they are produced, how they differ from each other, what phonetic features they possess, how they can be classified, etc. Phonology, on the other hand, aims to discover how speech sounds in a language form patterns and how these sounds are used to convey meaning in linguistic communication.
    (2) A phonologist will be more interested in it. Because one of the tasks of the phonologists is to find out rule that governs the distribution of [l] and [ɫ], [ph] and [p].
8. What is a phone? How is it different from a phoneme? How are allophones related to a phoneme?
答： A phone is a phonetic unit or segment. The speech sounds we hear and produce during linguistic communication are all phones. A phoneme is not any particular sound, but rather it is represented or realized by a certain phone in a certain phonetic context. The different phones which can represent a phoneme in different phonetic environments are called the allophones of that phoneme. For example, the phoneme /l/ in English can be realized as dark [ɫ], clear [l], etc. which are allophones of the phoneme /l/.
9. Explain with examples the sequential rule, the assimilation rule, and the deletion rule.
答： Rules that govern the combination of sounds in a particular language are called sequential rules.