As seen, a historical fit for Is. 19 was missing. Such a period in Egyptian history cannot be identified. However, above statements would make perfect sense as a prediction for the future, as of now.
OK, so all you have is an unfiulfilled prophecy. Since Assyria doesn't even exist as a nation anymore AND the then Caananite language the prophecy claims they will speak is a dead language, it's unlikely to be fullfiled, but hey, free beer tomorrow, right?