"Important" Pronunciation Stuff

I noticed it first about five years ago, a speech affectation that morphed "t" into "d" and sometimes dropped them altogether.  I first heard it spoken by teen girls -- ones that were friends with my daughters.  Now, however, the morphed "t" seems to be spreading.

An easy illustration of this phenomena can be found in the word "important."  The "t" dropping turns the normal

im-por-tant

into

im-por-dent

or even

im-por-ent

Yesterday, for the first time ever, I heard a newscaster using the second of these pronunciations.  Probably it is just a matter of time before I hear one using the even less desirable third version.

I have to confess this drives me a bit nuts.  It sounds unrefined.  Uneducated.  Lazy.  Where did this come from?  How do we stop it?  I realized that in the pantheon of modern problems this is probably number 6,345 but with a little effort it should be pretty easy to eliminate.

A few other similarly mangled pronunciations of the same type include

Not But-ton, but bu-un

Not eat-ten, but ea-un.

Yikes.  These pronunciations come with a guaranteed twenty point drop in apparent IQ.