The Inspired Speaker Academy
No! I don't mean say budder instead of butter! This is about being precise, not lazy. D and T are a plosive pair. That means the only real difference in making them is that one is voiced (D) and the other is unvoiced (T). Other than that, they are exactly the same!
I've been hearing a lot of splashy T's lately, the result of either a lazy or an over active tongue tip. The "splash" is usually caused by the tongue straying too close to the upper teeth, either upon contact or as it releases. The placement of the tongue for the letter T should be exactly the same as for the letter D, that is firm on the ridge behind your teeth. I've included a graphic here because it's hard to explain, please excuse my ineptitude with a pencil.
The tongue should move up to touch the ridge behind your front top teeth and then retract straight back into your mouth. If your tongue slips forward at the end of your T then you are being too enthusiastic!
Try this simple exercise of sneaking a T in with the D's to create a more precise, less explosive T.
1. d d d d d d
2. d d d t d d d t (x 4)
3. d d t d d t (x 8)
4. d t d t
(as many times as you can without letting the T run away with you)
If you notice the T is more precise at the beginning of the exercise but that your habitual splashiness creeps in near the end, repeat the second line over and over again until you can do the third without reverting, then repeat the third until you can do the fourth comfortably.
If you do any work with a microphone this exercise is very important. Too much air on a mic results in headaches for sound engineers and less than desirable recordings of your beautiful voice. You'll have to slow down at first when you practice in order to retrain your tongue, but once you have the knack you'll be able to return to your regular speaking speed.