Virtually all languages – even ancient ones – have a sort of language within the language which differentiates the formal written style from how the language is actually used, and how it is actually applied to everyday life is what formed slang.
Originally thought of as a language used exclusively by the non-educated lower class or disreputable people, slang has grown to be both universal as well as specific to certain professions. For its widespread usage, the actual origin of the word itself has remained largely unknown. Though there has been some suggestions that there is a Scandinavian link via the word sling, meaning “to throw” and slang being a specific language to quickly throw or express a point, a more plausible, yet unproven, explanation comes from the secret language used by thieves and beggars in Great Britain, in the early 16th century.
Though we all use it and have sort of become comfortable with it, slang can also be a problem. Consider the most widespread form of slang: slang through electronic communication, such as the acronym IDK (I don’t know), BTW (By the way), IMO (In my opinion), or the ever-present emoticons. As we see the first generation that has grown up always knowing electronic messaging, it has raised some specific issues: certain studies have cited more than 60% of school students using a form of shorthand that includes elements from texting or social networking. And, although teachers still widely understand and accept most of it, the practice is seen as a sign of worsening grammar and formal English skills.
While we can not pinpoint the origin of the word, we do know that it was first used in English in 1756 by William Toldervy in his 4 volume work, The History of Two Orphans, writing that, “Thomas Throw had been upon the town, knew the slang well.” Pointing to its lowly origins, Eaton Stannard Barrett, in The Setting Sun (1809), decries the fact that: “Such grossness of speech, and horrid oaths, as shewed them not to be unskilled in the slang or vulgar tongue of the lowest blackguards in the nation.” In two short decades (1827), the word had morphed to include the language of certain occupations, as we find in Jeremy Bentham’s Rationale of Judicial Evidence, “Giving, in return for those fees, scraps of written lawyer’s slang.” Coming full circle by 1871, George Eliot, in Middlemarch, writes that, “Correct English is the slang of prigs who write history and essays. And the strongest slang of all is the slang of poets.”
As for whether or not the current tidal wave of electronic-based communication will have a widespread effect on our understanding or formal English or not as time passes, sadly, we will not fully know until L8R.