In my country, England, I learned to speak English by copying my parents and other native speakers. I acquired the local accent.
But when I travelled 100 miles, what did I find? English was spoken in not quite the same way. There was a different regional accent. When I travelled 200 miles, the difference was very marked. When I travelled 300 hundred miles, I would occasionally have difficulty understanding what the locals were saying.
I expect the same thing happens in virtually every country and every language.
But here's a curious parallel in traditional jazz music.
A wise old jazzman told me many years ago that, when you move from region to region, you find the local jazzbands play some tunes in different keys from those to which bands in your own region are accustomed.
For example, all the bands in your area play a certain tune in Bb. But move 100 miles and you find that all the bands in that area go for C.
All the bands in your area play a tune in F. But in another region you find all the bands play it in Eb.
(Yes, the difference is nearly always one tone.)
In the years that followed, I was able to confirm the truth of this from my own observations. If you guest or deputise in a band 100 miles or more from your home, be prepared to play some tunes in keys that will feel unfamiliar.
How has this come about? My theory is that within each region the musicians deputise in each other's bands and build up over decades a kind of communal regional chord book.
An interesting phenomenon, isn't it?
