Language History courses

The origins of words, phrases, and the like has becoming more and more interesting to me over time. In the grammar course, the instructor gave a bonus addendum to one of his videos that talked about how different sections of England (16th Century maybe?) didn't understand many of the words each other spoke even though they were separated by only X miles. That course also illustrates all the different word types, but you know those may be relatively new. It would be interesting to have a course which talks about the history of language. What it was like 100's or 1000's of years ago and how it changes over time. Even as recently as the 18th century they were, for example, using "f" instead of "s" in their words. Why did that change? There must be things in (the English) language that I am blissfully unaware of that such a course would give us some enlightenment about how things change. Even today, our words and way of talking are in constant flux. I would run to this course if one was created.