Middle English V2: Compatible with a North Germanic source?

The new hypothesis that Middle English descends syntactically from Norse has been strongly contested by several specialists in ME syntax. One counterargument contends that ME Verb-Second patterns with Old English in sharing Verb-Third with OE but not Norse. The present paper argues that a Mainland Scandinavian adverb sa ‘so’, which appears after scene-setting adverbials (mostly PPs), is in SPEC(IP) and there blocks the common and expected UG order “PP — [IP subject — finite verb — …]” found in ME. When early Anglicized Norse lost this use of the sa adverbial, the UG order resurfaced in ME; this was not because of direct descent from OE.