The Runic Frisian vowel system: the earliest history of Frisian and Proto-Insular North Frisian

This article offers a phonological analysis of the vowel system of Runic Frisian (6th-9th c.) in stressed syllables. By using the most reliable attestations and taking them at face value, a vowel system emerges that can be the ancestor of all the later attested Frisian varieties, including the rather deviating Insular North Frisian dialects. The position of PGerm. *e-1 remains unclear due to scarcity of the data. In the short vowel system, the most outstanding features are the separation of fronted PGerm. *a from PGerm. *e (as is also the case in Old English). The most outstanding outcome in the long vowel system is the development of PGerm. *ai. Current reconstructions treat its monophthongisation as one process, contemporaneous with or even preceding the monophthongisation of PGerm. *au. This analysis proposes an early date of monophthongisation of PGerm. *ai in velar contexts and of PGerm. *au, and a later date of monophthongisation of PGerm. *ai in other contexts. The emigration of Frisians to the North Frisian islands in the 7th/8th century is positioned between those two stages. This reconstruction solves a long-standing problem in the historical phonology of Frisian, most prominent in the developments in Insular North Frisian and reconciles the main-stream opinions with a chronology of events as proposed by Hofmann (1964).