Culture as language, culture as dress. Burberry was a ww1 trench coat, the hunting shooting fishing set and then descended to be ambitious working class Essex Chav. Same with slang, polari was gay slang, BBC radio artful in-joke, normalised, now obscure.

Old is new is old. Kids hate nothing more than grandma throwing gang signs they learned from their elders not knowing the elder in question learned it from grandma first.

People probably get phd in the second order differential of slang rate of change.