Is the English Language Changing?

[tl;dr]

Everything you mention is a common feature of American English. American English has many dialects/sociolects, and that is the way those words are pronounced in them.

What you may have actually noticed is the proliferation of television stations with 24-hour news broadcasting, which means that they may:
(a) lower their standards for the pronunciation, enunciation, diction and delivery of their news casters, because they need many more people than before.

(b) present many more broadcasts/rebroadcasts of local news stations, most of which are not opposed to hiring newscasters with local dialects/pronunciation.

The truth is: many of us have a warped perception of what the "average" American English speaker sounds like, since editing of media often cleaned it up before we ever got to it. However, the modern trend toward "immediate broadcast" of all media means editing is being left by the wayside, and we are getting "unfiltered" language production.

There is also a growing trend for every individual (educated or not) to be placed in the media spotlight, or become a producer of media content (see barely literate twitter and facebook postings).

Welcome to your language, it's a much stranger and more varied place than you might have thought.