There are certain words and phrases I use that my parents generation wouldn't understand and vice versa. Historically speaking that must also be the case and that's how languages evolve. Is there any studies that attempts to quantify this inter-generational vocabulary barrier throughout history and the rate at which it evolves compared to modern times (e.g. how many generations does it take before the newer generation have problem understanding old text?) Sorry if this has been asked before or if this is a better question for the linguistics subreddit. *Edit: "Are there" English is my second language.