Why's it so hard to discover the origins (etymology) of slang words?

The difficulty in tracing the development of slang goes hand in hand with one of the great wonders of language: it is constantly evolving. This on-going evolution makes it virtually impossible to be certain of the precise origins of virtually all argot words or to discover the exact reasons for changes to that word over time. Take, for example, the word mec meaning guy in common French argot. The origins of this word have given rise to heated debate among French scholars and linguists who remain unsure of its precise origins leading to its first recorded (written) use in 1848. Some schools of thought believe the word to have stemmed from the old term meg (which is itself, in a sense, a slangy apocope of mégot meaning butt) which used to refer to smokers. Others believe the word is directly taken from the acronym MEC from mis en cause, which was written on the walls of the police stations in France in the 19^th century to indicate the room for people who were awaiting trial. The final faction (led by Henriette Walter) consider mec to be an abbreviation of maquereau (itself argot meaning pimp) as it was pronounced pre-1700 (mɛk.ʁo), with time evolving meaning to the current sense of mec as a bloke, while the word mac has retained the argot meaning of a pimp. If we then explore deeper into this one example, we can look for further progressions of the word mec in current French argot, and find that mecton is commonly used instead of petit mec, while mec itself has also been ‘verlaned’ to keum.

This example gives some insight into the immense complexity which arises when trying to deduce the etymology of slang words. This complexity is further compounded by slang’s primary use in spoken, as opposed to written, language. This means that any attempt to retrace the use and development of verlan prior to the invention of the microphone lacks certainty and relies on a certain amount of speculation. What is certain is that an outstanding force of nature seems to be continuously shaping the way we communicate and interact. Perhaps obviously – however strange it may seem – this evolution is caused by each individual’s environment shaping the way we use language. This is to say that we consciously adapt our use of language to change the way we are perceived by others and that our speech is also subconsciously influenced by the people and events which take place around us. In France, the power of this constant evolution of language between communities, races and nationalities and due to historical events is particularly applicable, with immigrants, wars, revolutions and technology all playing their part in what forms the French language, and in particular the slang, of today.