Old Frisian

Old Frisian was a West Germanic language spoken between the late 13th century and the end of the 16th century. It was spoken by Frisians who comprised a loose confederacy along the North Sea coast from around modern-day Bruges in Belgium to the Weser River in modern-day northwestern Germany. The vast majority of the surviving literature is composed of legal documents and charters, though some poetry, historiographies, and religious documents are attested as well. Surviving texts show remarkable uniformity across time and space, evidence of an early standard language for the Frisians.

Grammatically, Old Frisian generally marked for four cases, three genders, and two tenses, though more complex grammatical functions could be achieved through periphrastic constructions, where other words may be added to create different grammatical meanings. Its vocabulary had a variety of origins including loanwords from Celtic and Slavic languages. Latin loanwords and calques were relatively common as a result of Christianization. Word order in Old Frisian was varied; although its typical constituent word order was subject–object–verb, many different word orders are attested in the surviving texts.

Old Frisian is the common ancestor of all modern Frisian languages except for the Insular North Frisian languages, with which Old Frisian shares a common ancestor called or Proto-Frisian. Old Frisian was closely related to and shared common characteristics with the forms of English and Low German spoken during the period. Scholars have argued that the term Old Frisian is somewhat misleading, since Old Frisian was contemporary with other Germanic languages during their "Middle" period, such as Middle English and Middle High German. Although earlier scholarship contended that Frisian and English had a closer relationship to each other than to Low German, this is no longer the prevailing view.

By the 15th century, use of Old Frisian had begun to decline as the language was gradually displaced by Middle Low German as the language of trade in the North Sea. In the mid-16th century, a century-long internal conflict between two competing factions led to Frisia's subjugation by the Duchy of Saxony, which further displaced the language with Early Modern Dutch as the language of administration. No original Old Frisian compositions occur at all after 1450 and the last known work in the language was created in 1547, though writings made shortly thereafter suggest the Old Frisian used was probably already archaic by that point. By around the turn of the 17th century, the language is considered to have fully evolved into Middle Frisian, where it persisted mostly as a rural vernacular language.