资本的故事股份的力量:2) 免费学习美语发音 (#2: American English pronunciati...

2) 免费学习美语发音 (#2: American English pronunciation of the d sound and t sound) [原创 2011-03-24 12:26:26] 
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',1)">Welcome back to Seattle Learning Academy's American English Pronunciation podcast. This is podcast number two. My name is Mandy.
I hope you enjoyed our last podcast, the th sounds podcast. I also hope you went to www.pronuncian.com for more th sounds lessons and practice. Pronuncian.com is also where you can find transcripts and show notes to all our podcasts. Today's practice will be 5 sets of minimal pairs: dime, time; dense, tense; code, coat; tide, tight, and spend, spent. We'll come back to those later.
I introduced the concept of voiced and unvoiced sounds during the th sounds podcast. In case you've forgotten, we have both a voiced and an unvoiced th sound. I also hope you remember that the th sounds are a type of sound called fricatives. Fricatives are continuous sounds that are created by allowing only a small amount of air to leave the mouth. Today I am going to tell you about another kind of consonant sound, the stops. Specifically, we are going to explore the t sound (t sound) and d sound (d sound). These sounds are called stops because to create them, we briefly stop all air from leaving the mouth, and we then make the sound when the air is released.
Do you remember from last week's show that consonants often have voiced and unvoiced pairs? The d sound and t sound is another pair. Before we talk about how to correctly create the English version of these sounds, I want you to play with the inside of your mouth with your tongue. Don't feel silly, nobody can actually see you doing this. Notice that right behind your upper teeth, you have a hard, bony, bump. That bump was necessary for creating the friction of our th sounds last week. Then that bump rises and there is a slope up to the roof of your mouth, which is also hard and bumpy. Then, if you place the tip of your tongue all the way to the back of your mouth, you feel some soft tissue. We will keep coming back to these three places at the top of your mouth. I will call them the tooth ridge, that's that bump at the front, the roof of the mouth, that's the hard bony part in the middle, and the soft palate, that's the soft part at the back of your mouth.
Now, back to our d sound and t sound. When creating these two sounds, your tongue should briefly touch the front of the tooth ridge, then let go with a small puff of air. The difference between the sounds is the use of our vocal cords. In case you haven't noticed yet, the d sound is the voiced sound, and the t sound is the unvoiced sound. (d sound, t sound)
An error I specifically hear with the d sound and t sound is that the tip of the tongue is pressed against the roof of the mouth or at the very back of that ridge instead of at the front of it. This is called retroflexing, and it creates a different sound than the American d sound or t sound.
According to Wikipedia, retroflexing is not common among European languages, but is common for the languages of the Indian subcontinent. This very much agrees with my teaching experience. My students who speak Hindi, Tamil, and Punjabi all tend to retroflex their d sound and t sounds. It creates a hollow sound. If you are a native speaker of a language from India, pay special attention to these two sounds. Also, go to the Pronuncian webpage to see an illustration of where the tip of your tongue should be for these sounds.
Another error I hear is that many students don't allow the puff of air to come out after the initial stop of the sound. That puff of air is where the majority of the sound comes from and is even more important at the beginning of a word than the end of the word.
If your native language does not have both the t sound and the d sound in all parts of a word, it is likely that you will substitute one for the other. I hear students not voice the d sound more frequently than accidentally voicing a t sound, but it does go both ways.
Let's practice some d sound/t sound minimal pairs. I want you to notice the placement of your tongue during the sound, the puff of air that comes out of your mouth when the tongue releases, and whether the sound is voiced or unvoiced.
Ready? Repeat after me if you want the most benefit of this podcast.
dime, time
dense, tense
code, coat
tide, tight
spend, spent
Very good.
Most people who have visited or lived in the United States have noticed that we sometimes do some strange things to represent the t sound. We don't always say a t sound where we would see the letter t written. I promise I will come back to those strange issues in later podcasts. It is actually rather complicated, but there are guidelines to help you. For now, just work on correctly saying the sounds.
Understanding voiced and unvoiced sounds is also a key component of understanding -ed endings. We pronounce the -ed differently based on the last sound of the original word. I promise I will also address that in an upcoming podcast.
That's all for the d sound and t sound today. Don't forget to also keep practicing the sentence from the th sounds podcast, "Think about this thing, that thing, and those things" in addition to our 5 miminal pairs from today. Let's repeat those one more time.
dime, time
dense, tense
code, coat
tide, tight
spend, spent
Nice job everyone, and thanks for listening.