T-Rex: In the 15th and 16th centuries, spoken English changed dramatically, with vowels changing pronunciation and moving upwards in the mouth. Before it, we all sounded like ye olde-fashioned chumps. Afterwards, we all sounded hip and modern!
T-Rex: It was a century of kids outcooling their parents!
T-Rex: Before, "boots" was pronounced "boats", and feet like "fate". PRETTY OLD FASHIONED, dudes! But what's amazing is that the printing press was invented just before this started, and it was at that point that the spellings of words really got fixed. That's why English has so many oddly-spelt words! They show the pronunciation of words as they were, just before we underwent the Great Vowel Shift and decided to, you know, say everything differently.
Utahraptor: And nobody knows why it happened!
T-Rex: I know! It's so amazing!
T-Rex: Linguists are like, "Maybe immigration from the Black Death caused regional accents to be absorbed?" and then another says, "Maybe the English wanted to distinguish their language from the hated French?" and then they both shrug at each other!
Utahraptor: I don't think -
T-Rex: I saw it!!
Narrator: 15TH CENTURY ENGLAND:
T-Rex: Hey peasants! Tell all your friends to pronounce "boner" like "bone-air", okay? It'll make the future HILARIOUS.
Multiple off-panel voices: No way! However, maybe we WILL tell them to diphthongize their highest long vowels.
T-Rex: Guys! So not as cool!!