You're forgetting English is a far more confusing and ambiguous language.
"English" may mean a subset of British people, a language, or sometimes a restaurant MacGuffin, whereas "english" refers to only vertical spinning of a billard ball.
“The problem with defending the purity of the English language is that English is about as pure as a cribhouse whore. We don't just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary.” ― James D. Nicoll
I would secretly hope Harbrace printed no further editions and kids and crims didn't invent new cant. The only constants are change, death, taxes, the ineffective shrieking about the impending rhyming of history caused by dangerously-stupid leaders, and the co-evolution of language and culture.