Example
Cow -[Middle English cou, from Old English c; see gwou- in Indo-European roots.]
beef -[Middle English, from Old French buef, from Latin bs, bov-; see gwou- in Indo-European roots.]
Word History: That beef comes from cows is known to most, but the close relationship between the words beef and cow is hardly household knowledge. Cow comes via Middle English from Old English c, which is descended from the Indo-European root *gwou-, also meaning "cow." This root has descendants in most of the branches of the Indo-European language family. Among those descendants is the Latin word bs, "cow," whose stem form, bov-, eventually became the Old French word buef, also meaning "cow." The French nobles who ruled England after the Norman Conquest of course used French words to refer to the meats they were served, so the animal called c by the Anglo-Saxon peasants was called buef by the French nobles when it was brought to them cooked at dinner. Thus arose the distinction between the words for animals and their meat that is also found in the English word-pairs swine/pork, sheep/mutton, and deer/venison. What is interesting about cow/beef is that we are in fact dealing with one and the same word, etymologically speaking.
In other words, conquest of one society by another will lead to an interchange of words and phrases. Exploration and trade also contibuted to the enrichment of the english language.
An example not of latin roots
Canada
Ca·nadi·an (k-nd-n) adj. & n.
Word History: Linguistically, mountains can be made out of molehills, so to speak: words denoting a small thing can, over time, come to denote something much larger. This is the case with Canada, now the name of the second-largest country in the world but having a much humbler origin. Apparently its history starts with the word kanata, which in Huron (an Iroquoian language of eastern Canada) meant "village." Jacques Cartier, the early French explorer, picked up the word and used it to refer to the land around his settlement, now part of Quebec City. By the 18th century it referred to all of New France, which extended from the St. Lawrence River to the Great Lakes and down into what is now the American Midwest. In 1759, the British conquered New France and used the name Quebec for the colony north of the St. Lawrence River, and Canada for the rest of the territory. Eventually, as the territory increased in size and the present arrangement of the provinces developed, Canada applied to all the land north of the United States and east of Alaska.
references from
http://www.thefreedictionary.com/