A recent article in Science Daily has the headline `Linguist makes sensational claim: English is a Scandinavian language'. The claim in question is Jan Terje Faarlund's conclusion that `English is in reality a Scandinavian language' — that `Old English quite simply died out while Scandinavian survived, albeit strongly influenced of course by Old English.' The core of Faarlund's argument is that, in addition to many words that originally belonged to Norwegian and/or Danish, English has syntactic structures that are Scandinavian rather than West Germanic in origin. Specifically, Faarlund argues that `wherever English differs syntactically from the other Western Germanic languages — German, Dutch, Frisian — it has the same structure as the Scandinavian languages.' Faarlund then gives a few examples of syntactic parallelism between English and Scandinavian [that is, the Germanic languages of Scandinavia] and concludes that `the only reasonable explanation' for this parallelism `is that English is in fact a Scandinavian language, and a continuation of the Norwegian-Danish language which was used in England during the Middle Ages.'
Extraordinary claims require extraordinary evidence, as the saying goes. The evidence cited in the article is nowhere near extraordinary. Assuming that he is quoted accurately, there are some serious problems with Faarlund's claims.
First, some general comments about language contact. Faarlund says that `[e]ven though a massive number of new words are on their way into a language, it nevertheless retains its own grammar. This is almost a universal law….It is highly irregular to borrow the syntax and structure from one language and use it in another language.' He's mistaken in his belief that languages in contact can be counted on to retain their own grammar: there are hundreds of convincing examples of structural diffusion — including phonological, morphological, syntactic, semantic, and discourse features — in contact situations all over the world.
Here are a couple of examples. Probably the most famous case of all is Kupwar, a village in India in the border area between Indic languages in the north and Dravidian languages in the south. Morphosyntactic diffusion has been multidirectional in Kupwar, but the most extensive changes have affected the Kupwar variety of the Indic language Urdu, which has borrowed from the Dravidian language Kannada and from Marathi, the other Indic language spoken in the village. The changes include adoption of an inclusive/exclusive `we' distinction, subject-verb agreement rules in four different constructions, word order features, and about a dozen other features (details can be found in the 1971 Gumperz & Wilson article). Another striking case was reported by Andrei Malchukov in 2002: the Tungusic language Evenki has borrowed a volitional mood suffix and an entire set of personal endings from the Turkic language Yakut. It's worth noting that word order is the most frequently borrowed type of syntactic feature — a relevant point because two of Faarlund's examples of Scandinavian structure in English are word order features.
In short, there's a whole world of language contact phenomena out there. People borrow structures as well as words from their neighbors' languages, and people who give up their native language and shift to someone else's language make "learners' errors" that introduce foreign structural features into the target language.
Next, consider Faarlund's belief that the only reasonable explanation for parallelism between syntactic structures of Scandinavian languages and English is that English is a Scandinavian language: what about the possibility that English and Scandinavian languages independently developed some similar syntactic features? Parallel but independent innovations in closely-related languages are well known and reliably attested. The process is known as drift, and (apologies for oversimplifying slightly here) it results from structural imbalances that make particular bits of grammar hard to learn. English and the Germanic Scandinavian languages are all changed later forms of Proto-Germanic, and a thousand years ago (the relevant period when we're looking at intensive Norse-English contact) they were very closely related.
One of Faarlund's examples, for instance, is the split infinitive, which occurs in English and Scandinavian but not in West Germanic languages such as German, Dutch, and Frisian. But both English and Scandinavian have innovated an infinitive construction introduced by a particle (e.g. the to of the English infinitive phrase to go and the att of the Swedish infinitive phrase att regna `to rain'), while West Germanic languages other than English have no such thing — they have only an infinitive suffix on the verb, as in German Ich will gehen `I want to go'. There is no possible way to insert an adverb or any other word between a stem and a suffix; only in languages with at least a two-word infinitive phrase does the possibility of a split infinitive even arise, so it is trivially true that German, Dutch, and Frisian lack that possibility. It may well be that English and Scandinavian independently developed infinitive phrases introduced by a particle and then independently innovated split infinitives. (I don't know enough about the histories of these languages to know when the phrasal infinitives arose, so I don't know whether the innovation in English coincides with the period and location of intensive Norse-English contact.) Note too that the constructions are not completely parallel: Scandinavian languages retain an infinitive suffix, while English has lost its suffix entirely; and in Swedish, at least, the distribution of att is not uniform across either verbs or kinds of infinitive constructions.
Now, about old English-Norse contacts. In the following comments I'm relying primarily on the English case study that Terry Kaufman wrote for our co-authored 1988 book Language Contact, Creolization, and Genetic Linguistics — specifically his section `Norse influence on English' (pp. 275-306).
As Faarlund says, Viking chiefs and their descendants ruled the Danelaw for half a century (longer, in one area). The number of Norse settlers is estimated to have been in the hundreds (not thousands), so that they would have been far outnumbered by English speakers. How did the Norse and English speakers communicate (when they weren't killing each other)? The two languages wouldn't have been mutually intelligible at that period, but they would have been similar enough to make becoming bilingual easy. Or maybe they each spoke their own language and developed merely passive understanding of the other language. It is highly probable, at least, that the Norse had the prestige in the Danelaw — they were the rulers, after all. That's the easiest way to account for the hundreds of Norse loanwords in English.
After the period of Norse rule, when the former Danelaw was once again under English control, the available evidence indicates that Norse ceased to be spoken after just a few generations, about sixty years. One major piece of evidence for this conclusion is that all the objects with Norse inscriptions found in England were inscribed within sixty years after the end of Norse rule.
Faarlund comments on the striking differences between Old English and Middle English. One reason for these differences is that the vast majority of Old English materials were written in the West Saxon dialect, while most written Middle English was based (as is modern Standard English) on the dialect of London, a Midland dialect. These two dialects were quite divergent already in Old English times. The West Saxon kingdom was destroyed by the Normans in 1066, and with it went West Saxon as a written form; when writing in English picked up again, its center was London. It's quite true, though, that the dialect of London — in spite of being in an area that was not Norsified — later acquired a number of Norse features from people who immigrated from the former Danelaw.
Kaufman's survey of Norse influence on the English of the Danelaw focuses exclusively on phonological and morphological features. He counts 57 structural traits of Norse origin in Norsified English dialects, out of a total of at least 260 grammatical traits. That is, no more than 20% of the total set of comparable structural features of the most Norsified English dialects came from Norse. Even if Faarlund's percentage for the syntax turns out to be higher, his syntactic Norse features are unlikely to raise the overall percentage of Norse-origin structures to an unusually high level, compared to other instances of structural diffusion in intense contact situations. Moreover, 38 of the 57 Norse structural traits in those English dialects are (according to Kaufman) `mere phonological variants of what English had in the first place' — which makes them look like fashionable "accent" shifts rather than wholesale borrowings. The same is true of many of the Norse loanwords in English, among them sister, skirt, die, give, and guest.
Kaufman's conclusion: `The Norse influence on English was pervasive, in the sense that its results are found in all parts of the language; but it was not deep, except in the lexicon.'
Ironically, Faarlund's own scenario is a counterexample to his claim that grammar doesn't get borrowed: if, as he claims, English is a Scandinavian language, how did it get its numerous English structures? They would have to be borrowed from English, right? He emphasizes the borrowing into English of Norse grammatical morphemes; but the majority of English grammatical morphemes are native English forms, not from Norse. When he focuses on Scandinavian parallels to modern English syntactic structures, he says that these parallels exist `wherever English differs syntactically' from the other West Germanic languages; but this implies that there are syntactic structures in which English matches the rest of West Germanic — so again, if English is a Scandinavian language, it must have borrowed those English syntactic features. And English basic vocabulary items, in spite of all those Norse loanwords (and in spite of some French loanwords in the basic vocabulary) are mostly West Germanic in origin.
So it's English, not Engelsk. English, a West Germanic language whose closest relative is Frisian, with a substantial (but not an extreme) component of Norse-origin features in the lexicon and in all areas of the grammar. An interesting contact situation, with interesting results, but not out of the ordinary.