If they don't release the terminal consonant with a puff of air, then it becomes harder to hear any difference between, say, "bad" and "bat" (what pair of words were you thinking of?) And that extra puff of air can come across as affected or peremptory.In many languages, this terminal devoicing has gone from a frequent mannerism to a rule. So in German, "Rad" and "Rat" sound exactly the same, and they get lovely rhymes likeDu bist die Ruh, der Friede mild;Die Sehnsucht du, und was sie stillt.Don't know what this says about the German national character.
Most people do that. "Voiced" stops at the end of words are distinguished from "voiceless" ones by the shortness of the preceding vowel more often than by actual voicing. This is especially true when word-final stops are unreleased.
I first noticed it on adverts. But you get it here with the super-soothing Jerram Barrs - at 53 seconds - Church of Scotlant.https://www.youtube.com/watch?v=MxySk24J_bsIf everyone does it, then some people do it more than others!
Vera Lynn epitomized this. She was everybody's ideal mother.
@Crow - Bluebirts over the white cliffs of Dover?
Easy on there Bruce. Humour can prove the undoing of one so unaccustomed to displaying it. The old Dame had an almost unique way of enunciating the final 'T' on her sung words. Anybody else would have dropped that 'T' or had it sounding like a 'D'.