The "t" sound is omitted in differerent words from time to time. When people speak quickly, this tends to happen. It's not a sign of low class English, but it's not absolutely correct. It is representative of how the language sounds. We can call this: informal, typical, ordinary, every day conversation.Originally Posted by amigo
It depends on the person and the situation that one is speaking in. Different people will make it a point to use more careful pronunciation in certain situations. Some people might quite naturally switch back and forth from a more relaxed form of American English pronunciation to a more careful and standard form of American English pronunciation. It all depends on what the circumstance calls for. Then again, some people maintain the same manner of speaking for any situation.
A student once pointed out to me that I left out the "t" in mountain. And I thought to myself, "mm..... So I did. I left out the "t". I once caught myself leaving out the "t" when I said "on the left side". This happens when people speak quickly.
As far the words that you mentioned from the Ann Cook book go, I don't agree with that. I say the "t" in those words. I don't imagine that even when speaking quickly, I would leave out the "t" sound in those words.
If you want a good perspective on American English pronunciation, I suggest the following:
Listen to news announcers for good, careful, and standard pronunciation.
Watch movies and listen to talk shows in order hear a more relaxed, but usual and normal, style of American English pronunciation.
Different people in different situations speak differently. There is what I would call a "middle of the road area". However, it's very difficult to be precise about this. I suggest being very observant. Listen and imitate.