It is not a secret that the english language (alike almost every other) has passed different phases and has "suffered" influences from many different civilizations. As a result we may encounter words that come from its celtic past (like dog), its german/saxon heritage (the word hound comes from the equivalent of dog in german, hund), the Norman invasion and the french influence (many, more or less sophisticated terms, stem from this long period, like parent,joy, cream etc) and ofcourse the Latin and Greek languages (verbatim, kudos etc).
As the british conquered or colonised almost the half of the known world their language was influenced by all this expansion for good and especially in the area of commodities (spices, products) they introduced in europe dozens of words that today have become of international use.
The real Lingua Franca today is english and we always have to keep in mind that when speaking it, we are actually talking in a vast variety of languages.