\call Devoiced in consonant clusters with voiceless stops: play The post-palatal, or velar /l/: milk
第4单元 辅音 : 鼻腔音、延续音和旁流音
本单元我们将学习英语中的鼻腔音、延续音以及旁流音。鼻腔音与爆破音相同之处在于发音时气流在口腔某一处成阻。鼻腔音与爆破音以及所有其他音不同的是，发鼻音时口腔通道完全阻塞,气流只能通过鼻腔产生共鸣。英语的鼻腔音包括/ m、n、? /。
/ w /、/ r /、/ j /是延续音。发延续音时发音器官彼此接近，但无接触、无摩擦, 亦不产生爆破。
/ l /是旁流音。发音时，口腔中部形成阻碍，气流可从一侧或两侧逸出。 / m / / n / / ? /
/ m /和/ n /发音简单直接。/ m /是由双唇紧闭发出的音，发音时上下唇紧闭，舌身平放，软腭下垂，气流从鼻腔泄出。/ n /是个齿音，发音时舌头抵住上齿龈。/ ? /的发音部位与爆破音/ k /和/ ? /相同，舌后部触及软腭，堵塞口腔通道，双唇开，气流从鼻腔泄出。鼻音与爆破音、摩擦音以及破擦音有很大的不同，它具有某些类似元音的性质：可以自成音节。
大部分中国英语学习者发/ m /和/ n /都没有问题。我国某些方言中[ n ]和[ l ]是自由变异体，来自这些方言区的同学在学习中会有一些困难。分不清/ n /与/ l /主要的问题是将鼻腔音/ n /与口腔音/ l /混淆了。只要严格按照两种不同的发音方法去处理，问题是不难解决的。以下是/ m /、/ n /与/ ? /受语音环境影响而产生的不同变体。
/m/的音位变体：可自成音节，如 something; 位于前面的单词以/ m /音结束而紧跟着的单词又以/ m /为首时，延长发音时间，如 some more; 后接/ f /时发成唇齿鼻音，如 comfort
/ n /的音位变体: 在唇齿音/ f /或/ v /前齿化，如 invite; 在/ k /或/?/音前软腭化，如 think; 自成音节，如 button; 位于前面的单词以/n/音结束而紧跟着的单词又以/ n /音为首时延长发音时间，如 ten names;
/ ? /的音位变体: 后跟一个齿龈音时受同化而成为齿龈音, 如 taking ten; 自成音节，如 lock and key
/ w / / j /
/ w /和/ j /在三个方面很相似。第一，他们的发音分别与元音/ u: /和/ i: /相似，发音时气流在通道上基本不受阻碍，只是稍有摩擦，因此又被称作半元音。第二，/ w /和/ j /都不出现在英语单词的词尾。第三，他们是浊辅音。发/ j /时双唇呈扁平状，舌向硬腭抬起，略高于元音/ i: /，中间留有小缝隙形成不完全阻碍，气流从缝隙泄出时引起舌前硬腭间摩擦而成音。发/ w /时呈发/ u: /的姿势，舌向软腭抬起，双唇收圆，稍向前突出，气流在通过双唇时发生轻微摩擦而成音。现代语音学家将这两个音称作延续音。延续音的发音器官彼此接近，但与所谓“完全的”辅音如爆破音、鼻音以及摩擦音不同的是，它兼具元音与辅音的特点。
对于大部分的中国学生来说, 发/ w /和/ j /并不困难，需要强调的是发/ w /时双唇需要收圆。
/ r /
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另一个延续音是/ r /，发音时舌尖向上齿龈后部卷起，舌前部下陷略成凹形，舌身两侧向上弯曲，双唇略突出成圆形，气流由舌尖和齿龈后部间的缝隙泄出成音。注意舌尖不可接触上齿龈，否则就发成了/ t /和/ d /的音。
对于大部分的中国学生来说，发/ r /时会出现两种问题。一些学生用汉语普通话中的（r）音（如发“日”）代替/r/，汉语中的（r）听起来更像是摩擦音, 试比较”row” 与”肉”。还有些学生将其发成了闪音r，听起来像是在发英语的/ l /，而不是/ r /, 如将row说成low。记住发/ r /时略有圆唇。
/ r /的音位变体: 位于词首的/ r /，如right; 在清辅音群中清音化，如treat; 闪音/ r /，如very; 在/ k /或/ ? /后的/ r /舌位稍后移，如crate grey
/ l /
/ l /在英语语音中很特殊，发音时舌尖抵上齿龈，气流从一侧或两侧逸出。/l/与别的英语辅音不同之处在于：在众多的音位变体中，有两个显得特别突出，需要加以注意：“清晰”[l]：位于词首元音前，“模糊”[l]位于词尾元音后。“清晰”[l]在发音时舌前部向着硬腭略抬起，而“模糊”[l]在发音时则是舌前部稍压低，舌后部却朝软腭稍为抬高。
“清晰”[l]与汉语的（1）基本相同，需要重点练习的是“模糊”[l]：call, full, tall, fill。
此外，在学习/ l /音时，还要注意它与/ r /与/ n /的区别，如light, night, right。 / l /的音位变体: 舌伸向口腔最前部，形成“清晰”[l]，如, lease; 舌尖与舌叶位于后齿龈处形成“模糊”[l] call; 自成音节，如 bottle; 与清爆破音形成辅音群时清音化，如 play; 在软腭音前舌位稍后移，如 milk.
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Unit 5 Lesson Plan
Front Vowels & Central Vowels (教案：附要点、重点和难点)
Date: Oct. 14-18 Class: Classes 1, 2 & 3, Grade 2002 Subject: English Pronunciation Practice
Purpose:
The students will learn the consonants: Front Vowels & Central Vowels in English.
Objectives: Students will be able to :
1. Define - in their own words a definition for Front Vowels & Central Vowels; 2. Compare – based on the understanding of the basic concept, compare them with other vowels;
3. Practice – imitate the sounds and do practice.
Resources/Materials:
1. Textbook: Wang, Guizhen, An English Pronunciation Course, Higher Education Press, Beijing, 2000;
2. Handouts: illustration of the phonemes in focus; 3. Recordings of native speakers
Activities and Procedures:
1. Stimulating: Begin by asking the class to find out how much the students know about what they are required to learn. Make sure that it serves the purpose of stimulating the students to think about the issue and have the desire to find out the answers themselves.
2. Display examples by playing the recording of the native speakers showing the typical pronunciation in English.
3. Ask the students to listen to the tapes to make a good discrimination of the sounds in focus.
4. Have the students imitate the sound in focus.
5. Have the students share what they have learned by reading out the practice materials in pairs.
6. Have the students listen to the conversations recorded by native speakers of English and try to get the sounds in focus correct in their pronunciation.
7. Have the students practice the guided conversation. Ask them to pay special attention to the sounds in focus in speech.
8. Highlight the language function in the conversation in the practice.
9. Have several pairs of the students present their conversation in the class.
10. Comment on the students? performance by highlighting the achievement of the students and the efforts they need for the improvement.
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11. Ask the students to do more practice after class and get ready for presentation during the next session.
附: 要点、重点和难点
Unit 5
Front Vowels & Central Vowels
In this unit, we will learn the front vowels and central vowels in English.
Vowels are sounds in which there is no obstruction to the flow of air as it passes from the larynx to the lips. There are 20 vowels in English, among which 12 are pure vowels and 8 are diphthongs. The English pure vowels can be classified according to 1) the height of the raised part of the tongue; 2) the part of the tongue raised, and
3) the position of the lips, i.e. whether they are rounded or unrounded.
There are four front vowels in English: /i:/, /?/, /e/ and /?/. The reason these are called front vowels is that the tongue body is shifted forward, causing the vowels to be produced in the front of the mouth. In addition, the front vowels may be subdivided into those that are high (or close), like /i:/ and /?/, mid, like /e/, and low (or open), like /?/. For the two vowels in the high front space, /i:/ and /?/, the tongue is close to the hard palate. Likewise, for the low vowel /?/ the tongue is nearly flat and the lower jaw more open than for the other front vowels.
There are two central vowels in English: /з:/ and /?/ They are called central vowels because they tend to be produced at a point midway between the front and back vowels and between the high and low vowels.
It has become traditional to locate vowels on a four-sided figure. The following is a description of the four English front vowels and two central vowels.
i:
/i:/ & /?/,
/i:/ is a very common sound in the world's languages. It is made by raising the body of the tongue from its rest position and shifting it forward. The /?/ sound is made by lowering the tongue slightly from the high-front position for /i:/. Besides, /i:/ is a much more tense sound than /?/. The fact that English has these two high front vowels, differentiated by muscle tension in the root of the tongue, sets it apart from Chinese and many languages of the world. Both /i:/ and /?/ can occur in initial, medial, and final position in words.
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Very little difficulty should be encountered by the Chinese learners in the pronunciation of /i:/, but /?/ is a problem sound. It is easy for the learners to detect the difference in length. What counts here, however, is the difference in quality. It is therefore important to point out the fact that to pronounce a correct /?/, you need to
1) lower you tongue a little bit from the position for /i:/, and 2) make it a lax sound instead of a tense sound like /i:/.
The importance of correct pronunciation of /?/ lies in the fact that it is the second most frequent vowel in English. /e/ & /?/
/e/ is also an English vowel with high frequency of occurrence. The tongue body is shifted forward in the mid-plane. /?/ is produced by shifting the body of the tongue forward from its relaxed state, and lowering it from the position for /e/. It is the lowest of the front vowels. /e/ and /?/ do not occur in final position in English words.
/e/ and /?/ are not really problem sounds for the Chinese learners, but many of them fail to make a clear distinction between the two in their speech. The difficulty is that they have to make the clear distinction consistent. /з:/ & /?/
/з:/ and /?/ are central vowels. /з:/ is made with the tongue in the approximate middle of the mouth. It occurs only in stressed syllables. /?/ is also called a schwa. It is made similarly to /з:/, but with less tension. /?/ is the most frequently used vowel in English. Both /з:/ and /?/ may occur in all three word positions.
Most learners do not have problems in the pronunciation of /з:/ and /?/, still we need to give special attention to the schwa. The problem with the schwa may not generally be in production, but in knowing when to use the sound. No other vowel, with the exception of the other reduced vowel, /?/, is as important to an understanding of the English sound system and the way it functions in unstressed syllables.
第5单元 元音: 前元音和中元音
本单元介绍英语的前元音和中元音。
发音时气流由肺部泄出，不受任何阻碍，气流输出过程畅通无阻不带任何摩擦，这样发出的音叫做元音。
元音音素之所以彼此有别，是受到发音器官调节的结果。发音过程中发音器官采取某一固定位置直至发音结束的，是单元音，如/i:,u:/。双元音又称“滑音”，即在发音过程中发音器官的位置或形状有所变化，从一个单元音滑向另一个单元音，发/e?/这一双元音就是从发/e/开始，朝/?/的方向滑动，构成/e?/。 英语的元音中，有12个音元音，8个双元音。
单元音的音质取决于以下三个因素：一是舌头在口腔中位置的高低，即舌头前、中、后哪一部分抬得最高；二是牙床张开的大小，即张口程度是合、半合、还是开；三是唇形，发音时唇形是扁平还是圆唇。在元音发音的过程中起关键作用的是舌头，因此学习元音时就要重点学会正确调节舌位。元音的音素也正是根据发音时舌位的变化情况进行分类的。单元音可按发音时舌头前、中、后哪一部分抬得最高而分成三类：前元音，中元音，后元音。这一单元我们学习的是英语
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