It’s often stated that Americans pronounce T like D. This is not quite accurate. In American English, T and D are always pronounced distinctly in words like dip and tip, or attack and adapt, or bleat and bleed. However, there are many words, such as metal and medal, or bleating and bleeding, or bitter and bidder, where T and D are indeed pronounced the same for many speakers of American English. In these words, it is not the case that T is being pronounced as a D. Rather, it is the case that both T and D are being pronounced as a third sound, commonly known as a “tap” or a “flap.” The “tap” that we may hear in a word like bleating is not the same sound as the final consonant in bleat, but it is also not the same as the final consonant in bleed. We do not find the “tap” sound in all positions in a word in American English. We only find it between vowels. Specifically, we only find it between vowels when the following vowel is not stressed. Stressed syllables are indicated in our dictionaries by one of two marks, either the high stress mark, /ˈ/, for a syllable which has the greatest degree of stress in the word, or the low stress mark, /ˌ/, for a syllable which doesn’t have the greatest degree of stress in the word, but which still receives stress. Any syllable not preceded by one of these two marks is unstressed. Thus, we may hear the “tap” sound in words like metal, bleeding, or bitter, but we would not hear the “tap” in words like attack, since the vowel following the T is in a stressed syllable. It should be noted that R acts like a vowel in American English with regards to tapping, thus words like barter, herding, or aorta will have taps. Also, a “tap” can be found at the ends of words when the following word begins with an unstressed vowel. For example, in the sentence "I will read a book," the D at the end of read will sound like a tap. Not all speakers of American English pronounce T and D as taps in the situations mentioned. Some will keep T and D distinct in all situations. Tapping of T and D is also not common in British English though it is common in Australian English. Even some speakers who do use taps might not always do it consistently, and might pronounce a word with a tap sometimes, and with a regular T or D other times. A learner of English who wants to keep T and D distinct in all situations will be understood. However, if you want to sound like a native speaker of American English, it is useful to learn when to pronounce T or D as a tap.
看了一篇文章，贴在下面，说人家不是读 d， 是弱 t，是 tap, 或者 flap. 如果这篇文章是对的，我的问题是：弱化的 t 和 d 有什么区别? 这个tap 是怎么发出来的？
我看过一些 youtube 视频，就是说在 非重读的情况下，t 就读成 d。
大家怎么看？
It’s often stated that Americans pronounce T like D. This is not quite accurate. In American English, T and D are always pronounced distinctly in words like dip and tip, or attack and adapt, or bleat and bleed. However, there are many words, such as metal and medal, or bleating and bleeding, or bitter and bidder, where T and D are indeed pronounced the same for many speakers of American English. In these words, it is not the case that T is being pronounced as a D. Rather, it is the case that both T and D are being pronounced as a third sound, commonly known as a “tap” or a “flap.” The “tap” that we may hear in a word like bleating is not the same sound as the final consonant in bleat, but it is also not the same as the final consonant in bleed.
We do not find the “tap” sound in all positions in a word in American English. We only find it between vowels. Specifically, we only find it between vowels when the following vowel is not stressed. Stressed syllables are indicated in our dictionaries by one of two marks, either the high stress mark, /ˈ/, for a syllable which has the greatest degree of stress in the word, or the low stress mark, /ˌ/, for a syllable which doesn’t have the greatest degree of stress in the word, but which still receives stress. Any syllable not preceded by one of these two marks is unstressed. Thus, we may hear the “tap” sound in words like metal, bleeding, or bitter, but we would not hear the “tap” in words like attack, since the vowel following the T is in a stressed syllable. It should be noted that R acts like a vowel in American English with regards to tapping, thus words like barter, herding, or aorta will have taps. Also, a “tap” can be found at the ends of words when the following word begins with an unstressed vowel. For example, in the sentence "I will read a book," the D at the end of read will sound like a tap.
Not all speakers of American English pronounce T and D as taps in the situations mentioned. Some will keep T and D distinct in all situations. Tapping of T and D is also not common in British English though it is common in Australian English. Even some speakers who do use taps might not always do it consistently, and might pronounce a word with a tap sometimes, and with a regular T or D other times. A learner of English who wants to keep T and D distinct in all situations will be understood. However, if you want to sound like a native speaker of American English, it is useful to learn when to pronounce T or D as a tap.
如何想歪了？
我也想歪了，不过我只明白T，不懂D
我感觉大部分人读成 sdudent
还没听过student 读成像"纠”的。
额，这个不是美音独有的，t在s后面都发d。楼主说的是water里的t之类的，英式发t，美式基本发d。
同意。
这个也不是英文独有的，很多语言都有这样的浊化，日语里也很多
这楼不错
Stay里的tay的音跟day还是有区别的，只不过中国人听不太出来（因为中文里没有这个音）
https://www.goalsenglish.com/lessons/flap-t-sound-american-english-accent
就是s后面的t发成了d。跟education的du发音近似 不是纠也不是丢也不是杜。就是国际音标 dju的发音
这是在s后面的元音重读的情况下才把清辅音读成浊辅音，楼主说的是词尾的发音轻读，两回事。
嗯，我觉得说清辅音浊化不准确，应该是失去爆破，和浊辅音是不同的音。好像法文里面的gâteau和cadeau，难倒一群人
没有D哪来的T？
会的
对，edu不管什么国家都是发成纠。
美国人都是把T去掉，发成sir嗯。
被老美纠正过water的发音-挖的。那我以前学的是英式英语。