I've heard people pronounce the /t/ at the end of a word smoothly and naturally, as in 'light', 'night',...But when i say that /t/ at the end, I feel like i'm making a another syllable /tə/. Any ideas?
An English /t/ at the end of a word is usually pronounced without any audible release if there is no following vowel.
There are three stages in the production of a plosive sound /p, t, k, b, d/ or /g/:
First, there is the approach phase. This is when the lips or the tongue start to move to block off the air from the lungs to prevent it from leaving through the mouth.
Second there is a hold phase. This is when we have blocked off the air and the air pressure builds up behind the blockage as it is pushed upwards from the lungs.
Thirdly there is the release phase. In a typical plosive, as the air behind the blockage is suddenly released, we get audible plosion (think of the word explosion) as the air suddenly shoots out of the mouth.
However, how we pronounce a plosive depends on there it occurs within a syllable or word. A word final plosive will very often be pronounced without any audible release phase in English - so long as the next sound is not a vowel. So to achieve a more English word-final /t/, you should think of the /t/ finishing at the end of the hold phase. Think of it as not having any release phase at all.
Phonetics note: Of course there is a release phase for every plosive - it is just that it is inaudible. Unreleased stops result in death!
I'm Korean actually. You might be disappointed that I'm not a certified English pronunciation trainer either. But here I'll list out steps that have worked well out for me, so please if this works for you then be sure to vote it up.
The zeroeth step is to "forget the t you know." English pronunciation should be established separately, along with your native language pronunciation. So even when this doesn't come off as comfortable at first, please try memorizing each sound as steps to making it, or you'll get totally confused later because so many sounds sound so similar. (I gave up my "established" pronunciation because I kept failing at distinguishing "p"s and "f"s and "f"s and "th"s.) If you know how to make each of the sound, your brain will be able to handle it in a variety of ways (not only relying on your "ear", but also other parts of your brain participated in making such sound as well), yielding you clearer response. I don't know technical details yet.
- Give a little tension to your jaws, pulling them a little closer to your throat. This works for Koreans like me.
- Notice the tension right in your lower jaw. It is the addictive sense that keeps you use the tension.
- Say, "JAW," with your mouth open very wide. When making the sound, drop your jaw. Or alternatively, "PATH" should work.
- Relax your tongue. Let it naturally move to slightly just tap your incisors.
- "Shoot" your breath- sorry, I had no other expression in stock.
- Your tongue in touch with your incisors detach and make the desired sound.
- If you feel like you're actually making a somewhat "ch"-ish sound, give tension to your "buccal mucosa," as if you were making an uncomfortable/sarcastic smile, and then try again.