Physically, the two sounds are produced identically as far as the position
of the vocal organs (lips, tongue, teeth, facial muscles, palate, etc) are
concerned, the difference between the two being solely that a 'd' is voiced
and a 't' is unvoiced. (Thus most speakers will say "budder" rather than
"butter" in spontaneous speech).
When you're pronouncing 'd', you're already pronouncing a 't' anyway - just
adding your voice. So when you finish vocalizing a word ending with '-nd',
there would be a kind of residual 't' sound, already there by default.
My response to David's question is that how clear that 't' sound is would
depend more on the individual speaker than any other factor.
There could also be a link with the phoneme (or silence, as in a glottal
stop) immediately following the -nd word, but while trying to formulate a
theory I felt like the centipede who found he couldn't walk as soon as he
started trying to analyse how, so I gave up!
Of course, a final 'd' may often have quite a clear 't' pronunciation in
many '-ed' words (asked, voiced, helped) - but I think this is a separate case.
Colin McKinney
col...@loxinfo.co.th
Khon Kaen Vithes Suksa Bilingual School
257 Laonadee Road, Tambon Banwa, Amphur Muang, Khon Kaen 40000, Thailand
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