The Great Vowel Shift

Why did the great val shift happen? Amas iis a name to put around a period of time. Or was there something happening that made it happen at that moment? That's a big question. Some people think it had to do with the plague and the disruption of populations, the growth of london and the influx of people from various parts of the country. It also happened so slowly over so long a time, that whatever kicked it off, we can't really say in any one instance why people who used to say mate started saying meat. Because it has to shift quite a bit before someone takes note and says, hey, that's a strange pronunciation. But by that time it