The language we now know as English is a product of the numerous invasions of warlike peoples into the British Isles. The Angles, Saxons, Jutes and Frisians were all Germanic-speaking peoples whose original territories stretched from Holland to the Danish peninsula, and who took over England in the early 5th century AD. Frisian (spoken today only in coastal and island areas of the Netherlands) remains the closest living relative to English. What we now know as Old English is a hybrid of these tongues with traces of Latin, brought by the previous Roman rulers of Britain.
Danish rule really only lasted until 954, yet this period would leave a lasting impact on the English language.
Many English words beginning with th originate from Old Norse, although the sound did already exist in Old English. Examples:
Likewise, most English words starting with sk are Norse in origin, such as:
Given the seagoing ways and cold northern homeland of the Vikings, it makes sense that they brought into English a number of words that reflected their lifestyle and origins. Aside from the aforementioned skate and ski, there is also:
wake (the nautical term)
Other Norse-derived words include anger, ugly, knife, troll, boulder, slang, tackle, whore, keg, husband, egg, bun, clown, cake, freckle, window, gate, and many more. There are some which are possibly Norse in origin but are more ambiguous; because Old Norse and Old English are Germanic in origin, they share many similar words, so it is not always easy to tell which was a Norse introduction and which is simply a similar word of Anglo-Saxon provenance.
We owe many common English names to the Danish invaders. Eric descends from the common Norse name Erik or Eirik. Garth comes from the Old Norse word for a forest clearing. Howard appears to be a variation of the Scandinavian Havard.
Probably the most common Norse contribution to English names is the addition of the patronymic -son at the end of a word. A patronymic is a name component that indicates the person's paternal ancestry, and it is common in different forms throughout Europe. So Andersson is the son of Anders, Williamson is William's son, and so on. (Parallels are the Spanish -ez, Serbian -ic, Russian -ov, Ukrainian -enko, Scottish Mac- and Irish O'.)
Numerous place names are Norse in origin too.
The suffix -by means yard, farmstead or village. This is seen in place names such as Grimsby, Normanby, Rugby, Selby, Barnby and Sotheby. This is also the origin of the term by-law, meaning the law of a local area.
Thwaite means "meadow" in Old Norse and appears in place names such as Braithwaite and Langthwaite.
Thorpe is another Norse name for village, and is seen in place names like Winthorpe and Scunthorpe.
The names Tuesday, Wednesday, and Friday are named after the Old Germanic gods that both the Anglo-Saxons and the Vikings believed in - Tiw (Norse Tyr), Wodin (Odin) and Frige (Freyja) . But they are from Old English and thus predate Viking contact. However, Thursday does bear the stamp of Norse influence. In Old English it was called Thunorsdag, named after the god Thunor (meaning Thunder). It is very similar to the German equivalent, Donnerstag. However, the Danish referred to Thunor as Thor, and thus it became known as Thorsdag in Danelaw, which crept into the language of the rest of England. Over time Thorsdag became Thursday.
The Normans, who were later to conquer England and have an even more profound effect on its language, were of Viking stock (their name Norman means "north men"). The Normans were Vikings from Denmark and elsewhere who settled in Northern France and adopted the local language and culture, but they did contribute quite a few words into the vocabulary of Modern French, particularly nautical terms.
The Norse influence in England is more prominent in the Northeastern areas that were part of the old Danelaw. Yorkshire is the most obvious example, where Norse words live on in local slang; arse is the example of a Norse-derived word that was originally Yorkshire dialect slang, which has subsequently passed into the broader English vernacular. There are hundred of place names in Yorkshire with -by and -thorpe, and the accent bears a distinct Norse stamp as well. There's a good example of this here at the British Library's sound recordings. You can also check the next couple of clips for comparison. Don't worry about the content - the first is a interview with two footballers in Danish, the second is a caricature of the Sheffield accent (South Yorkshire). Maybe you can see some similarities.
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