Speaking correctly

I'm no language snob, but for the most part I feel like I have a fairly good grasp on the English language. I have a casual register that I use all the time, but I also know how and when to use my formal register. I am guilty of chopping the "g" off words that end in "ing". I regularly say, walkin', talkin, jumpin', etc... I also sling around my share of woulda, coulda, shoulda, wanna, and gonna. But when the chips are down, I can turn that off and speak properly. See below a list of language offenses I do not commit, but are quite common.