I am teaching a class of Chinese students (plus one Saudi Arabian and one Iranian). They are graduate students who have all studied English for many years, and perhaps were under the impression that they spoke English when they arrived on our shores. They were rudely greeted by professors who gave incomprehensible lectures, and the general public which insisted in speaking fast and incomprehensibly as. All of us who have studied second, third, and fourth languages know the feeling.
I was working with them on a minimal pair yesterday, “t” and “d”. One is voiced, and one is voiceless, but the mouth is in basically the same position to make both sounds, and these two sounds are common to most languages, though they may be pronounced slightly differently.
I gave them a list of words beginning with either “t” or “d” — tap, drive, trunk, tender, television, dare, dumb, etc. They got those very well.
We moved on to words which have the “t” or “d” in the middle — better, bidder, writer, rider, letter. They discovered that the t’s in the middle of words were actually pronounced “d” if they were between two voiced sounds, such as vowels. They tended to give full value to the “t,” which was not how Americans speak. There is not enough time to withdraw from a voiced sound, d, speak a competing voiceless sound, t, and then return to a voiced “d.”
The most important difference between “writer” and “rider,” however, is a slightly lengthened preceding vowel (a diphthong)– “raaaiider” and “wraider.” This was very hard for them to catch, and they didn’t do so well on this one, but we practiced it and perhaps their ears have gotten more attuned to the differences.
Then we went on to t’s and d’s at the end of the word — hat, had, shot, set, part, hard, wend, bend, cart. (It is always good to include a word like “wend” which the students would probably not know so that they do not follow expectations, but rather pure sound.) The success rate for this pattern was also pretty low.
The difference between the final “d” and the final “t” is barely perceptible, and slight lengthening of the “e” sound in “wend” as compared to “went” is very sophisticated phonology and probably will not be achieved by a speaker of English as a second language. We are not talking high tech phonology here, but the ear of the second language speaker. Once again, the actual sounds made at the end of these words are barely different from each other — both the “d” and the “t” are swallowed. It’s almost as if the speaker is saying, “I’ve given you enough information on the front end — you have to figure out how it ends.” Since there is no voiced vowel following the final “t” or “d” there is no need to voice it if it stands alone so it sort of disappears into thin air.
This is just single word listening. It got REALLY interesting when we put words together!