Methodological Reflections on the Emergence of Old Frisian

The question addressed in this article is whether it is possible to identify the time of the emergence
of Frisian from the rest of West Germanic. Some of the criteria used in determining the chronology
of Frisian language history are evaluated in terms of their temporal and spatial aspects. Phonological
features that appear to differentiate languages from a present-day perspective disappear in a haze
of synchronic and diatopic allophonic alternations. Reconstructions of the order of phonological
developments often turn out to be best-fit interpretations of changes whose precise character, age
and location are hard to determine. Besides, reconstructions of regional distribution are obscured
by subsequent migrations and dialect shifts. Consequently, the splits in a language family tree
are not bifurcations, but bushes of variation, where only hindsight allows an identification of the
chronology and the decisive factors involved.