Mohammad, people will always understand you if you pronounce a crisp T (British style). If you live in the US, you will gradually pick up the softer flapped T which occurs in certain positions under certain stress patterns. American English has four /t/ sounds: [tʰ] [t] [t̚] [ɾ] - aspirated [tʰ] (with a puff of air) as in "tray." - unaspirated [t] (without air) as in "stray." - unreleased [t̚] as in "fat" (varies regionally, some people have an aspirated "fatuh.") - flapped [ɾ] (a brief [t] sound which almost sounds like a [d]). "Metal" sounds very close to "medal." Depending on the speaker, the usual flapped T between vowels for an unstressed syllable can be a flapped T (common) or a crisp T or a full D. And in very relaxed speech, /t/ can become /d/ - What are you doing => wuduh yuh doing? Here is a youtube video about flapped T and the other versions of T: https://www.youtube.com/watch?v=_3zbmyUu8-s

First of all it is "flipped" not "flapped" Flap is what a bird does with its wing Do american people always flap T sound to D sound when it's between two vowels? This isn't true and Protect does not have a D sound in it. Even trying to think how it would sound with different American accents it still only has T sound to me

Hello, I think what you have in mind might be when there is a double T. For example, 'Little' (sounds a little like liddle), 'Battle', 'Cattle', 'Bottle', etc. Another one that might confuse you is Italy- pronounced a little like I-Da-Ly. Not exactly sure why here ... As for how you phrased your question, I would say "When do 'T' sounds pronounced like 'D' in (speaking in) American accents?" PS. this is my first answer on iTalki so forgive me if I'm not 100% correct.

No, we don't always do it. It's also a regional thing. To me, the T in "protect" doesn't sound like a D. Maybe to foreigners it does, but it is clearly different than predict. It may be pronounced less crisp than a Brit, but I'm not sure. I'm not sure on the rules of the T/D, but it would be a safe assumption to pronounce the T like a D. As you listen to native speaker more, you may pick up on certain words or patterns where this isn't the case.

"Protect" (pronunciation [ prəˈtɛkt ]) is stressed on the second syllable. As the T is followed by a stressed vowel, the T is pronounced as a regular T and not as a flapped T. "Metal" (pronunciation [ ˈmɛdl ]) is stressed on the first syllable. As the T is followed by an unstressed vowel, the T is (usually) pronounced as a flapped T. I actually pronounce it as a T, not a flapped T.