Language is in a constant state of flux based on changing geographical and social circumstances. Though the actual vocabulary is variable, this manner of speaking is the most widely accepted in the country. But we are all aware of a set of standard features in our language. But slang is by definition nonstandard language. If you wanted your brother to move away from the TV and you began by saying, 'Excuse me sir,' he'd be shocked.
Slang is one form of nonstandard language that has been used in the United States.
Coleman and Hornyak have their own opinions of this view. They have a good laugh over this. There's different clothing for different situations, just like there's different language for different situations. We also add words to our standard vocabulary when we christen a new invention. Literally, it refers to a vehicle that transports something or someone.