Approximately 1,000 words that can be identified as having Viking roots have been added to the English language. As early as the eighth century, Vikings had an influence on the development of the English language.
The influence on the English language was a result of the Viking invasion of England in the late 700s. This invasion, and the subsequent truce between the two sides, resulted in increased interaction between the Vikings and the English, allowing for the integration of new words into the English language.
In Old English manuscripts, approximately 150 words of Norse origin appear. However, more Norse words were assimilated into oral language and were used in written texts more frequently in the following centuries.
English language speakers use many words that have Viking origins, including husband, egg, want, smile and odd, on a daily basis. Even the days of the week were influenced by Vikings. Thursday is said to have stemmed from the Viking belief in the Norse God Thor, hence "Thor's day." Pronunciations of the words they, them and their were also influenced by Norse grammatical structure.
Many words associated with war also have Viking influence. Club, ransack and slaughter sound and look very similar to their Viking origins words of klubba, rannsaka and slatra.