The language of the Anglo-Saxon settlers appears not to have been significantly affected by the native British Celtic languages which it largely displaced.
The number of Celtic loanwords introduced into the language is very small, although dialect and toponymic terms are more often retained in western language contact zones (Cumbria, Devon, Welsh Marches and Borders and so on) than in the east.
However, various suggestions have been made concerning possible influence that Celtic may have had on developments in English syntax in the post-Old English period, such as the regular progressive construction and analytic word order, as well as the eventual development of the periphrastic auxiliary verb "do".
These ideas have generally not received widespread support from linguists, particularly as many of the theorized Brittonicisms do not become widespread until the late Middle English and Early Modern English periods, in addition to the fact that similar forms exist in other modern Germanic languages.

Old English contained a certain number of loanwords from Latin, which was the scholarly and diplomatic lingua franca of Western Europe.
It is sometimes possible to give approximate dates for the borrowing of individual Latin words based on which patterns of sound change they have undergone.
Some Latin words had already been borrowed into the Germanic languages before the ancestral Angles and Saxons left continental Europe for Britain.
More entered the language when the Anglo-Saxons were converted to Christianity and Latin-speaking priests became influential.
It was also through Irish Christian missionaries that the Latin alphabet was introduced and adapted for the writing of Old English, replacing the earlier runic system.
Nonetheless, the largest transfer of Latin-based (mainly Old French) words into English occurred after the Norman Conquest of 1066, and thus in the Middle English rather than the Old English period.

Another source of loanwords was Old Norse, which came into contact with Old English via the Scandinavian rulers and settlers in the Danelaw from the late 9th century, and during the rule of Cnut and other Danish kings in the early 11th century.
Many place-names in eastern and northern England are of Scandinavian origin.
Norse borrowings are relatively rare in Old English literature, being mostly terms relating to government and administration.
The literary standard, however, was based on the West Saxon dialect, away from the main area of Scandinavian influence; the impact of Norse may have been greater in the eastern and northern dialects.
Certainly in Middle English texts, which are more often based on eastern dialects, a strong Norse influence becomes apparent.
Modern English contains a great many, often everyday, words that were borrowed from Old Norse, and the grammatical simplification that occurred after the Old English period is also often attributed to Norse influence.

The influence of Old Norse certainly helped move English from a synthetic language along the continuum to a more analytic word order, and Old Norse most likely made a greater impact on the English language than any other language.
The eagerness of Vikings in the Danelaw to communicate with their Anglo-Saxon neighbours produced a friction that led to the erosion of the complicated inflectional word-endings.
Simeon Potter notes: "No less far-reaching was the influence of Scandinavian upon the inflexional endings of English in hastening that wearing away and leveling of grammatical forms which gradually spread from north to south.
It was, after all, a salutary influence.
The gain was greater than the loss.
There was a gain in directness, in clarity, and in strength."

The strength of the Viking influence on Old English appears from the fact that the indispensable elements of the language – pronouns, modals, comparatives, pronominal adverbs (like "hence" and "together"), conjunctions and prepositions – show the most marked Danish influence; the best evidence of Scandinavian influence appears in the extensive word borrowings for, as Jespersen indica
The language of the Anglo-Saxon settlers appears not to have been significantly affected by the native British Celtic languages which it largely displaced. The number of Celtic loanwords introduced into the language is very small, although dialect and toponymic terms are more often retained in western language contact zones (Cumbria, Devon, Welsh Marches and Borders and so on) than in the east. However, various suggestions have been made concerning possible influence that Celtic may have had on developments in English syntax in the post-Old English period, such as the regular progressive construction and analytic word order, as well as the eventual development of the periphrastic auxiliary verb "do". These ideas have generally not received widespread support from linguists, particularly as many of the theorized Brittonicisms do not become widespread until the late Middle English and Early Modern English periods, in addition to the fact that similar forms exist in other modern Germanic languages.
Old English contained a certain number of loanwords from Latin, which was the scholarly and diplomatic lingua franca of Western Europe. It is sometimes possible to give approximate dates for the borrowing of individual Latin words based on which patterns of sound change they have undergone. Some Latin words had already been borrowed into the Germanic languages before the ancestral Angles and Saxons left continental Europe for Britain. More entered the language when the Anglo-Saxons were converted to Christianity and Latin-speaking priests became influential. It was also through Irish Christian missionaries that the Latin alphabet was introduced and adapted for the writing of Old English, replacing the earlier runic system. Nonetheless, the largest transfer of Latin-based (mainly Old French) words into English occurred after the Norman Conquest of 1066, and thus in the Middle English rather than the Old English period.
Another source of loanwords was Old Norse, which came into contact with Old English via the Scandinavian rulers and settlers in the Danelaw from the late 9th century, and during the rule of Cnut and other Danish kings in the early 11th century. Many place-names in eastern and northern England are of Scandinavian origin. Norse borrowings are relatively rare in Old English literature, being mostly terms relating to government and administration. The literary standard, however, was based on the West Saxon dialect, away from the main area of Scandinavian influence; the impact of Norse may have been greater in the eastern and northern dialects. Certainly in Middle English texts, which are more often based on eastern dialects, a strong Norse influence becomes apparent. Modern English contains a great many, often everyday, words that were borrowed from Old Norse, and the grammatical simplification that occurred after the Old English period is also often attributed to Norse influence.
The influence of Old Norse certainly helped move English from a synthetic language along the continuum to a more analytic word order, and Old Norse most likely made a greater impact on the English language than any other language. The eagerness of Vikings in the Danelaw to communicate with their Anglo-Saxon neighbours produced a friction that led to the erosion of the complicated inflectional word-endings. Simeon Potter notes: "No less far-reaching was the influence of Scandinavian upon the inflexional endings of English in hastening that wearing away and leveling of grammatical forms which gradually spread from north to south. It was, after all, a salutary influence. The gain was greater than the loss. There was a gain in directness, in clarity, and in strength."
The strength of the Viking influence on Old English appears from the fact that the indispensable elements of the language – pronouns, modals, comparatives, pronominal adverbs (like "hence" and "together"), conjunctions and prepositions – show the most marked Danish influence; the best evidence of Scandinavian influence appears in the extensive word borrowings for, as Jespersen indica
Old English