The linguist David Crystal has suggested a future in which we are all \”bidialectal\”, with one English to talk to the world and another to use at home.
The thing is though, I thought we all did that anyway.
Agreed, my experience is unusual in that I\’ve spent most of my adult life outside the UK (OK, OK, unusual for a Brits, obviously, there are billions upon billion who spend much or all of their life outside the UK). Much of that in non-English speaking countries.
At one level I might point to the various flavours of German. High German, as used on the TV news programmes and by serious people in serious meetings. And then what is actually spoken by people in the streets and the homes. Saxon is very different from Schwabian, from Schweizer Detsch and so on. Mutually incomprehensible. Certainly as extreme as Geordie to Cornish (the accent in English, not the Gaelic).
But even at the family level this is still true even if to a much lesser extent. Code words, favourite phrases, words that trigger specific memories and thus have different from public meanings.
As I say my experience is coloured by having been abroad for years. But I certainly speak a different English outside the house and in. It\’s instinctive now, that I speak more clearly, using a more precise vocabulary (often the more \”complex\”, Latin based than Anglo Saxon based, presumably if I lived in Northern Europe it would be the other way around) and more slowly (all of which are indeed changes in accent if not dialect) outside the house than inside it.
To the point that when in the US I could and did talk to my (English) inamorata in English without any of the Americans around us having a clue what we were saying, while speaking to the Americans in entirely understandable if to them accented English/American.
Perhaps bidialectical just means that people will do this more than they do now: but I\’m pretty sure that all of us do it right now to at least some extent.