BUNDLES OF ISOGLOSSES dialect x dialect y Isoglosses often occur in bundles, resulting in different dialectal areas with a transition zone between them.
J.K. Chambers and Peter Trudgill, Dialectology. Cambridge 1980 Chapter 7. Boundaries
“The Rhenish Fan”
STRUT/FOOT BATH/TRAP
(Chambers and Trudgill) Fuzziness of phonological isoglosses: 1. Mixed lects This is the area where STRUT words are variably pronounced with or . The figures show the percentages of STRUT words pronounced with : 100 indicates they all are; 50 that only half of them are; 0 that none are. I.e. 0 means a full FOOT-STRUT Split, while 100 means there is no split. (Chambers and Trudgill)
(Chambers and Trudgill) Fuzziness of phonological isoglosses: 1. Mixed lects Northern Southern Northern predominant Southern predominant (Chambers and Trudgill)
(Chambers and Trudgill) Fuzziness of phonological isoglosses: 2. Fudged lects Hatched areas show vowels which are neither nor . (Chambers and Trudgill)
Trees or waves?