An 'isogloss' refers to a specific type of language border.
It is based on the actual language border between the sprachraums but is not utterly identical.
However, an individual isogloss may or may not have any coincidence with a language border.
This migration created the modern language borders in Switzerland.
A language border or language boundary is the line separating two language areas.
This also explains why a language border (isogloss) runs through Holungen.
Allowing for easy cross language border alerting, through automatic translation of the missing child poster.
Localities along the language border have usually both a German and a French name.
The western end of the route runs close to the Franco-Dutch language border.
They are separated by a language border that has constantly moved back since the Middle Ages.