Prior to meeting my wife I would say the word 'across' with a 'T' on the end. I probably picked that up from my rural Indiana childhood. My wife would cringe when I would say 'acrost' and would quickly correct me. She threatened to carry a squirt gun and shoot me every time I said the word wrong. I have since learned to add a silent 'T', and just keep it to myself.
Other words that have been dropped or being pronounced differently from when I was young:
ain't...I stopped using that word long ago
crick...flowed into creek eventually
worsh...cleaned up into wash
get me some, as in "I'm going to get me some worms for fishin"...I'll say that for the fun of it at work to get under the skin of a couple people.
Words that ended in 'ing' had a silent g...I now pronounce with the full 'ing'
My grammar/spelling is definitely in the "C / C+" range, so it is hard for me to throw stones.
But keeping with the theme of the thread, I would have to say my biggest gripe is the use of texting abbreviations when typing emails at work. OMG that is annoying.