In words, as fashions, the same rule will hold; Alike fantastic, if too new, or old: Be not the first by whom the new are tried, Nor yet the last to lay the old aside.
On the whole I try to keep Modesty and Willie in timeless settings, which is why I avoid all the latest slang and in-words. It won't be long before 'brill' sounds as dated as 'super' does now. [Uncle Happy, 1990]
The downtrodden are the great creators of slang.
I have always loved the fluidity of language - delighting in dialects, dictionaries, slang and neologisms.
The earliest dictionaries were collections of criminal slang, swapped amongst ne'er-do-wells as a means of evading the authorities or indeed any outsider who might threaten the trade.
All slang is metaphor, and all metaphor is poetry.