I think it’s easier to support the idea that tribes broke off from Germany and went to Britain and Scandanavian than from Scandinavia to Britain.
Did you actually READ the article?
No one is claiming a different history than what is known: England is Anglo-Saxon & Norman, after those 2 groups invaded—and the native Britons moved off to Wales, or intermarried with the Germans and Normans...
HOWEVER, right before the Norman conquest, England was ruled by Denmark for around 30 years—and the researchers claim sentence structure and grammar in English is more similar to Scandinavian languages than it is to German. The researchers are claiming that the basic structure of the LANGUAGE has more in common with Scandinavian languages than German—not anything weird about our history.
I will say that of non-native English speakers, the Scandinavians are the best. I’ve known Swedes that sounded just like Americans.
They told me it was because American movies are not dubbed into Danish, Norwegian, Swedish, as they are in German—so everyone grows up hearing American-accented English in movies from the time they are small children.