I am wondering this sort of cross-linguistically. I know many (most?) languages don't have a word for "the", but the English language does. First part of the question is, did Middle English and Old English have this? It looks like Old english did,
Old English developed from a set of Anglo-Frisian or Ingvaeonic dialects originally spoken by Germanic tribes traditionally known as the Angles, Saxons and Jutes.
Did those languages have a word for "the"? If not, then this would sort of answer the question. Then I would know that it was invented relatively recently which would give us a ballpark time frame required for the evolution of such a language construct. If they had a word for "the" all the way back then though, we might not be closer to an answer of how long it takes for this sort of concept to be introduced.
Do we have any other cases of words like "the" which we saw were introduced in a language, language variant, or new language evolving from some old one?
Basically I want to see how long it might take to introduce such a subtle concept as "the" (or "a", or probably some others). Or perhaps, knowing the reverse would be helpful too. Are there languages we have examples of for which they dropped the terms for "the" and the like, and the future/current language no longer had them?
I recently read that Latin didn't have articles, but did Italian/Spanish evolve from Latin to have articles? That would be interesting. It also says Sanskrit doesn't have articles, but other modern Indian languages do. That might be an interesting candidate to study, how it evolved. That and all Slavic languages (like Russian), except Bulgarian and Macedonian, don't have articles. Might be another candidate?