It is, indeed.
But it's normally changing over dozens of generations. What we have here is mostly educated vs uneducated.
Each American generation comes up with it's own lingo, but this isn't that.
Examples of that would be terms like low-key, no cap, dead-ass, I'm dying, 304s, gucci, and the exhausting "LET'S GOOOOO"
On a long-enough timeline, we'll have totally separate languages.