Hadar Shemesh explains the flap T in American English, the quick tap sound that /t/ and /d/ make between vowels in unstressed syllables. Your tongue taps just behind your teeth, fast and light. Hear it in words like "writing," "riding," and "activity."
Chapters
Riding a book and riding a motorcycle, they sound practically the same. Let's talk about the flap T. The T that appears between two words that actually sounds like a D. So the T that appears between two vowels in unstressed syllables is pronounced like this. The tongue goes up and taps slightly right behind the teeth as in the word writing. Just like writing a book. Writing a book. So it's not a D. It's not writing a book, it's not a T. In American English, writing a book sounds a little bit like an R, right? Writing, writing a very short R. The word writing is also writing with a D. So the D between two vowels also sounds like a flap T. So just so you know, when the T appears between two vowels or when the D appears between two vowels, just pronounce it like a very, very light D. Writing it is wedding order, get it? Activity, greater party, harder attitude.