The history of English spans several thousand years, from its earliest recoverable origins in linguistic prehistory to the modern varieties of English spoken today. The study of its evolution takes into account both internal history (the historical development of its linguistic forms, including changes in phonology, morphology, syntax, semantics and lexicon) and external history (social and geopolitical events bearing on the development of the language). Linguists divide the history of English into several general periods, as follows:
Proto-Indo-European (PIE): the earliest known ancestor of English, Proto-Indo-European is a reconstructed protolanguage, spoken by nomadic tribes known as the Indo-Europeans in the Pontic-Caspian steppe region of Eastern Europe circa 3,500 BC. PIE is reconstructed on the basis of comparative evidence from languages belonging to its 10 branches (Anatolian, Indo-Iranian, Greek, Italic, Celtic, Germanic, Balto-Slavic, Tocharian, Armenian and Albanian).
Proto-Germanic: the protolanguage ancestral to all Germanic languages, spoken by Germanic tribes in the Pre-Roman Iron Age (5th/4th - 1st century BC) in lower Scandinavia and northern Germany. All Germanic languages reflect the signature innovations of Proto-Germanic, including the operation of Grimm's Law and Verner's Law as well as the emergence of the so-called dental preterite ending (continued by the -ed past tense marker of English). With the expansion of the Germanic peoples across Europe during the Roman Iron Age (1-400 CE), the Germanic branch split into three sub-branches: East Germanic, North Germanic, and West Germanic, the latter giving rise to English.
Old English (OE): The pre-Old English period (ca. 450-650 CE) begins with the fifth century CE settlement of Britain by speakers migrating from a West Germanic dialect area near the North Sea coast of Europe. This speech community included seafaring Germanic tribes, such as the Angles, Saxons, Jutes, and Frisians, who spoke varieties of Anglo-Frisian, as this dialect subgroup is called. In the centuries following the Anglo-Saxon migration and settlement overseas, the version of Anglo-Frisian spoken in Britain developed independently, and thus came to diverge from its linguistic relatives on the Continent. By the seventh century Old English had emerged in writing, and the written tradition of OE would continue into the 11th century. By contrast with later periods of English, the Old English lexicon is almost purely Germanic, with comparatively few loanwords from other languages. Scandinavian influence (owing to the Viking invasions and occupation of England during the late OE period) is mainly in evidence later, with most Norse loanwords appearing first in Middle English texts.
Middle English: the Middle English (ME) period (ca. 1100-1500) saw English undergo dramatic changes. Following the Norman Conquest of 1066, French became the official language of England and held this status until well into the second half of the 14th century. Numerous borrowings entered the English lexicon, and many common English words were replaced by their French counterparts; significant borrowing from Scandinavian and Latin appeared as well. The lack of a unifying, official English standard led to striking dialect differentiation across England. Sound change and morphological change resulted in less flexible word order. By the time of Chaucer (1343-1400), English was once again the dominant language in England, yet much transformed from its Anglo-Saxon ancestor.
Early Modern English (EModE): English of the Early Modern period (1500-1700) is notable especially for standardization and the growth of the lexicon. The trend toward standardization owed much to the spread of printing as well as increased access to education and the growth of literacy. During this period the English lexicon was enriched by heavy borrowing from Latin, Greek, French and other languages. Many of the disparities between English spelling and pronunciation would arise during the Early Modern period due to the effects of the Great Vowel Shift.
Modern English (ModE): Inconsistencies in English spelling persisted into the Modern English period (1700-present), but the publication of Samuel Johnson's Dictionary of the English language (1755) did much to promote uniformity of spelling in England. Noah Webster's American Dictionary of the English Language (1828) was similarly effective in America. During this period prescriptive grammarians sought to codify standard usage even further. The English lexicon was much enhanced during this period by contact with other cultures via colonialism, trade, and migration from abroad, especially to the United States. New terminology also emerged from technological advances of the Industrial Revolution. Literacy grew further as a result of public education and the spread of public libraries. By the twentieth century, numerous varieties of English would be spoken around the globe.