It is often suggested that other linguistic evidence provides clear proof that the Scandinavian settlements were on the scale of massive folk migrations. Scandinavian pronouns, verbs and other everyday words, such as the words for husband, knife and window, were adopted by the English language. Some have contested that such changes could not have occurred unless the Vikings were in a majority, but other linguists have persuasively argued that it is misleading to draw conclusions about numbers on the basis of linguistic changes (see Ekwall 1930; Hines 1991; Page 1971; Townend 2000). They suggest that the influence of one language upon another depends on their relative status, and by the need to borrow words to describe new things. It is unlikely that ninth-century Northumbrians would have been able to understand Danes and Norwegians easily. Communications would rely on the few individuals who knew both languages. Nevertheless, the similarity between Danish and English would have meant that it was easy for English to adopt Scandinavian words. In particular, the introduction of a large number of Scandinavian words associated with farming indicates that there was an influential Danish-speaking farming population. Most evidence suggests that Scandinavians adopted English fairly rapidly, adding a few of their own words. Vernacular inscriptions from north and east England show a clear continuity in the use of English from the eighth to the eleventh centuries. There is now evidence for Scandinavians continuing to use either their runic script or their own language in England.
Julian D. Richards, 2007, “Viking Age England”, The History Press, p. 62-3