There are some cases in history where academic writing (seen in government and religious documents) differs so greatly from the actual language of the people (which those very same government employees and clergy use when outside of their professional environments) that the two languages are more like distant cousins.

Of course, it's the popular language which evolves into the language of today, while leaving the ancient, once "proper" language behind where it belongs.

And then, that region's language prescriptivists of today say that the version they were taught is the right one, all over again 😅