What are the dividing lines between "versions" of English through history?

I’ve enjoyed it a LOT. It begins with proto-indoeuropean and moves along providing a ton of history, culture, and neato language facts and hypotheses. I’ve got to admit that some of the episodes are more interesting than others, and while the 3 episodes on the Great Vowel Shift contained some real delightful stuff, some of the grammar/pronunciation discussion was not very exciting for me. Still worth it, though. I just wish I could retain all the fascinating bits.

'splains a lot about why English spelling is so messed up, it does.

Everyone knows the Great Vowel Shift was so we didn’t pronounce vowels like the French.

But it made it so we don’t pronounce vowels like the Germans.

The Great Vowel Shift made it so we don’t pronounce vowels like anyone. It’s one of the things that make English hard for non-English-speakers to learn.

Them too.

Yeah, it was joke.

Anyway, the sounds associated with tense/long vowels are different, so written vowels are different and some cognate words are off.

English is not unique in having a vowel shift. Other languages have had vowel shifts, too, including Chinese and Greek.

That’s correct. During the second half of the 16th century a major change occurred in the English verb, especially in the modals which changed from verbs to a new category (“modals”) and the rise of the periphrastic constructions like “be able to” and “have to”. Before about 1550, it would have been perfectly normal to say something like, “He must can move faster.” By 1600, that phrase had disappeared to be replaced by “He must be able to move faster.” This shows that “can” is no longer a verb, but in a different category that cannot be governed by a modal. In both French and German such phrases are still possible.

There is a book by David Lightfoot called “Principles of Diachronic Syntax” that goes into this in detail.

Newspeak?