two totally separate dialects in the north of English engaging in a bit of horse-trading

The lovely AnnaS misremembers slightly. It was two separate languages: English and Danish, as spoke over a thousand years ago. They discovered that they had many roots in common but the declensional endings were miles apart. They decided to drop the declensional endings and instead to use word order to indicate case. Quantum leap in the development of the language we know and love and argue interminably about.