The northern dialects of Britain and Ireland have verbal agreement patterns that differ radically from those of Standard English: the children is singing vs. they are singing vs. they sing and dances. This so-called 'Northern Subject Rule' (agreement with adjacent personal pronoun subjects, but invariable verbal -s everywhere else), attested since the time of Middle English, was once a consistent, categorical grammatical system in the older dialects. It continues in the modern vernaculars in the form of complex variable systems, amalgamated from traditional dialectal patterns, Standard English forms, as well as modern supraregional vernacular influences. This study explores the variable use of verbal agreement forms in Scotland, northern England and Ulster, based on data ranging from the mid-20th century »Survey of English Dialects« up to dialect recordings of the 1990s. In analysing continuities and discontinuities between the different dialects involved, it also raises questions of a theoretical nature: what are the implications of these hybrid, variable systems for a usage-based theory of grammatical competence? Die Verbkongruenz in den nördlichen britischen Dialekten weicht auffällig vom Standardenglischen ab. Doch was in älteren Formen dieser Dialekte ein in sich geschlossenes System mit kategorischer Geltung war, tritt in modernen Varietäten stets variabel und in einer Vielfalt von Mischformen auf. Die Arbeit untersucht anhand von Korpora Kontinuitäten und Unterschiede zwischen den Dialekten dieser Region und diskutiert die Bedeutung solcher hybrider, variabler Systeme für eine Theorie der grammatischen Variation.