Though how the English language came into existence remains a mystery to many people, linguists believe that English and most other European languages have descended from a common source: the Indo-European parent language. English was first spoken by the Anglo-Saxons who invaded England in the fifth century. They passed onto us the basic vocabulary of English. In over fifteen centuries of its development, English has enriched itself by massive borrowing. As British immigrants landed in America and established the United States as an independent nation, a new variety was added to the English language: American English. Though some people worry that the language is running out of control, many native speakers of English take pride in the tolerance of their language.