If one were interviewing someone for a key executive position and it came down to two people, should their use of heavy slang make or break them?
If you want to be successful in certain areas, then it is necessary to speak in a way in which others understand you.
When I was a freshman in college taking Speech 101, there was a young white male that had such a heavy heavy Southern accent that you could barely make out a word he was saying. Poor guy... this was an accent he was dealing with...not a choice of using slang. Later I became friends with the T.A. and we discussed this great guy. He told me that although this young man was very intelligent and made good speeches, his accent could hold him back. I remember every time he spoke, the class would become dead quiet and everyone just sat in awe listening to him.
He spoke very good English. It was just his accent that was so heavy... There is a difference in having an accent vs. slang'... I have a very bad habit of saying "yall" and "ain't"...but even on CF I find myself typing the words and then erasing them as to not come off as some hick. I also know that these words are incorrect.