"The creatures outside looked from pig to man, and from man to pig, and from pig to man again; but already it was impossible to say which was which." ― George Orwell, Animal Farm
We were doing this before LLM's. All sorts of trendy business speak would spread - the term "synergy" springs to mind as one people beat to death.
This is the concept of "memetics" (as in meme) in action. Hank Green recently talked about using AI and he went "off script" and threw "I appreciate the pushback" into his speech on the fly...
LLM's generating large volumes of content means that we're going to see all of its "isms" creep into other peoples speech much faster.