"Slang ... an attempt of common humanity to escape from bald literalism, and express itself illimitably ... the wholesome fermentation or eructation of those processes eternally active in language, by which froth and specks are thrown up, mostly to pass away, though occasionally to settle and permanently crystallize" –Walt Whitman, 1885
My younger sister and I sat at our family dinner table on Easter Sunday, salivating over the aroma of my mother’s stuffed leg of lamb. Our father made his way from the bedroom to the table to join our pre-dinner chatter.
"BT Dubbs,"1 said my sister, "your celly2 was blowin' up3 like woah4 while you were at yoga in the am."5
"For realsies?"6 I asked. I hadn’t checked my cell phone since that morning. "Did you answer?"
"After the third call, yeah. It was Jay. He sweats you7 hardcore."8
"Whatevs.9 I’ll call him later."
It was at this moment of polite conversation that our father abruptly slammed his fist on the table. "Speak English!" he cried.
"Oh Em Gee!"10 replied my sister, "Freak out why don't you, Dad?"
My father, attempting to curb his temper, lowered his voice and said, "I'm sick of this. I can't understand a single word you girls say to each other anymore. You sound uneducated. My daughter the writer sounds like she can't speak the language." He was referring to me.
Of course, I can speak the language. In fact, I can speak it so well that I choose to finesse and manipulate it into a shorthand language, that is, slang. Merriam-Webster defines slang as:
"an informal nonstandard vocabulary composed typically of coinages, arbitrarily changed words, and extravagant, forced, or facetious figures of speech."
I pretty firmly believe that slang is not spoken for a lack of language comprehension. Rather, it demonstrates a hyper-awareness of the language, and an understanding of the culture surrounding it.

When my sister says "BT Dubbs," it is her slang for "by the way." But by using her slang version, she refers to much more than the literal expression "by the way." By saying the letters "BT" she is referring to the common typing or texting shorthand, where that phrase is abbreviated to "BTW." However, my sister is so culturally enlightened that she goes one better, and changes the "W" in "BTW" to "Dubbs," as in "Dubbya," a nickname for the middle initial of our president, George "Dubbya" Bush. So what she has done in that one quick phrase "BT Dubbs" is made her explicit point clear (the literal "by the way"), and clued me in to the fact that she is savvy about online or text speak, and is aware of our current political climate. That's how slang works. It makes a word or phrase do more than just a job of literal communication. It personalizes your language.
Furthermore, the "informal" aspect of slang is what makes it inappropriate in so many contexts, such as on tests or when speaking with strangers. So, by using slang, you are assuming a comfort level with the person with whom you speak. To speak slang to someone is to assume that they, too, understand the cultural currency and outside references of your unorthodox vocabulary. Slang speak then becomes a club, either you are in and understand the code, or you aren't.
Those who aren't in on the slang, usually view it as illegitimate or uneducated. James C. Fernal once referred to slang as the "advertisement of mental poverty." This is because they are missing part of the message. All they hear is the destruction of the literal phrase, but they cannot perceive the additional codes. So of course, it does sound like nonsense. Or it sends a different message entirely.
A great mystery was solved in my family once my father got the ball rolling about our uneducated English. For months, my mother had been shouting very loudly when leaving voicemail messages on my sister's cell phone. "CAN. YOU. PICK. UP. SOME. MILK!! LOVE. YOU!" It was at this Easter dinner where we discovered the reason. My sister’s voicemail message requests that the caller leave their message in the form of a "shout out." Our hapless but well-meaning mother assumed there must be a problem with her voicemail that made it difficult to hear.
But what does all of this add up to? Our dad was still annoyed that he couldn't understand us, and no amount of explaining would undo that. Yet, my sister and I still relished our slang speak. It does appear to be a matter of time and place. Because of its informal nature, slang simply doesn't work in every context (So please don't add "OMG" to your history papers). Apparently one such inappropriate context is my family dinner table. Most slang comes and goes with the times, but some of it eventually makes a permanent place in mainstream language. After all, "hot" didn't always mean "cool," and "cool" didn’t always mean "good." These are slang terms that we've grown to accept. This is how language develops and changes. Eventually, everyone catches on.
Our mother made her way over to the table with the succulent dish of lamb. She looked laughingly at our father, "Lighten up, Sam. Srsly."