The story of English is certainly one of roaming and settling, invasions and war. English has literally come from nowhere to conquer the world.
Interestingly, in the early days of the the Raj, Sir William Jones, a British judge who was stationed in India, presented the results of his investigations into ancient Sanskrit because he originally wished to become familiar with India's native law codes. While doing so, Jones discovered that Sanskrit bore a striking resemblance to Latin and Greece. For example, the Sanskrit word for father, pitar, differs little from the Greek and Latin pater. From further investigation, Jones concluded that the Sanskrit language shared a very strong affinity with Greek and Latin; thus, they all could share a common source.
In contemporary times, linguists have agreed that about one-third of the languages derive from this Indo-European "common source." These include the European descendants of Latin, French and Spanish, Russian, the Celtic languages, Irish and Scots Gaelic, and the "offshoots" of German, Dutch and English. Evincing further what Sir William Jones discovered, the Brothers Grimm of Grimms Fairy Tales fame established beyond doubt that the German word vater (and the English father) has the same root as the Sanskrit/Latin pitar/pater.
That the Indo-European languages were in Europe and not from the fertile crescent of Mesopotamia, a theory exploded by nineteenth-century archaeology. is evinced by the discovery of vocabulary. Today the most widely accepted theory places the environment of the Indo-Europeans in a northern climate in which words for snow, beech, bee and wolf have an important place. Also, because none of the prehistoric languages had a word for sea, conclusions have been made that the Indo-Europeans must have lived somewhere in northern central Europe, people whose descendants are now found in Greece, Italy, Germany, and the Baltic. It is also worthy of note that both the Rhine and Rhone rivers are believed to have names derived from the Indo-European word meaning flow.
The Indo-Europeans lived a nomadic life, and some of them began to travel east; after time, the Indo-Europeans started drifting west towards the more temperate climates. Thus, their descendants are found in Greece, Italy, Germany, and the Baltic, leading to the commonalities in these languages with German and English and Dutch as these tribes also moved further west to what is now the British Isles. Some linguists feel the word should not be Indo-European, but Indo-Germanic, but others contend that the Indo-European nomenclature is appropriate because they extended into Southern Europe. Of course, Romans came into Britain in 55 B.C. and Latin certainly entered the mix.
One authority writes,
This is not to say that there were no split-offs. Some of the modern river names in Britain, for instance, are Celtic, not English (Avon means river), and smoe have Roman-British names: Lindum Colonia became Lincoln, derived in part from the Welsh Ilyn, which means lake. The Germanic conquerors of Britain were all Saxons, and gradually the Anglo-Saxons began farming, so the vocabulary came from Old English, derived from Old French and Germanic forms. Gradually, too, old Latin words were given new meanings. Add in the Viking invasions after the Normans of 1066 also supplied more vocabulary to the developing English.