The Danish Creolisation Hypothesis

A pidgin develops when slaves from many language backgrounds are obliged to communicate with a lexicon from the colonial language but no help with syntax. Their children then create a new syntax with the loanwords. Here is an example from the Jamaican creole.

A: Bredrin, wa gwaan? B: Bwai, ya done know seh mi deya gwaan easy. A: Yes I, a so it go still. Not ‘n na gwaan, but we a keep di faith, nuh true? B: True. How de pickney dem stay? A: Bwai, dem aright. B: Yeh man, lickle more, seen? A: Lickle more.

You can hear that the lexicon is mainly English, but the syntax is not. Jamaican has no morphology at all, but uses single-word aspect markers. stay    present habitual aspect of to be in /de pickney dem stay/. a is an aspect marker    I run (habitually) /mi a ɹon/.

In a creole these features of the lexifier language are removed:
conjugation; declension; grammatical gender; number; tense; embedded clauses
consonant clusters; aspiration; diphthongs; syllable codas (endings)
tones (Chinese, Yoruba, indigenous languages of the Americas)
These features are introduced, so pidgins resemble isolating languages
aspect markers, e.g. -a/ -en
reduplication (e.g. “big-big”) to represent plurals and superlatives
nominalization, verbification, adjectivization

England had been ruled from Denmark for a few generations, but then English kings took over again. The hypothesis is that Danes who were obliged to speak Old English in the 11th century acquired a pidgin of single words without grammar. Their children then created a grammar. Although Norman French was the high language, it seems to have had little effect for a century or more. Middle English then borrowed heavily from French, but did not modify its phonology or syntax.

“Get” is by far the most widespread loanword in MnE.
It is essential for the hundreds of English phrasal verbs we use in everyday speech. geta was Old Norse for “be able”, “reach”, “learn” etc. It is from Proto-Germanic getan from PIE root ghend- “to seize, take.” It is Modern Icelandic for “can”, “be able”
“Get” is so useful that you could replace almost any English verb with a “get” phrasal verb. Sometimes, as in get up, it is difficult to find a French-origin alternative.
get bread/ a job/ the door obtain a direct object or knowledge
get in/on/up/back/by/over/behind add a preposition
get going/dressed/finished/working add a participle

Phrasal verbs were common in Old Danish, but not in OE, which had inseparable-prefix verb such as forbærnan ‘to burn up’. Modern German allows prefix separation. Phrasal verbs with other auxiliaries, such as have and put probably originate in the EME period. Many cannot be searched in dictionaries and are quite odd etymologically:
put up with it; put one over on him; get off on something;
Separable pronouns, sometimes two, often finish up at the end of the utterance:
what do you take the bottle top off with?

In the East Midlands there seems to have been a sudden change two generations after the Norman conquest. The Anglo Saxon Chronicle was still being updated, but the English changed dramatically in the 45 years between the following two entries.