Barm, bap, cob or roll? Mapping Britain's bread roll lines from 20,000 survey answers

Britain has many words for a bread roll. I combine two published dialect surveys, Our Dialects (11,609 located answers) and the Dialect and Heritage Project's Great Big Dialect Hunt (8,463), to map where people say roll, bun, bap, barm, cob, breadcake, teacake, muffin and batch. Answers are smoothed with an adaptive Gaussian kernel (8 km where answers are dense, chosen by cross-validation) and the lines where the leading word changes are drawn. Roll is the national default (46% of 20,038 answers) and holds a majority across southern England and Scotland, but north of a line from Cardigan Bay to the Lincolnshire coast the map breaks into regional blocks: cob in the East Midlands, barm around Manchester and Liverpool, breadcake around Sheffield and Hull, bun in the north-east, bap in north Wales, Staffordshire and Northern Ireland (88% of answers there). The two surveys agree closely on where each word is strong (county correlations 0.68 to 0.99), and agree reasonably with YouGov's 2018 county statements and with most claims in Wikipedia; Wikipedia's claim that bun is the Northern Irish roll is not supported. Cob is given less often by younger respondents in its heartland (odds ratio 1.11 per decade of age), but no clear age slope appears for batch. The names of 614,437 UK food businesses carry only a thin version of this map: barm appears in 3 names, but cob shop names cluster strongly in the East Midlands and butty names in the North West. Survey answers are copyright of the Our Dialects project and the Dialect and Heritage Project (University of Leeds); they are used for aggregate analysis with credit, and only aggregates (areas with at least 10 answers, and smoothed surfaces) are published here. Interactive version: https://tristan-hotham.github.io/bread-rolls/. Data and code: https://github.com/Tristan-Hotham/bread-rolls. Blog post: https://blog.tristanhotham.com/2026/10/27/bread-rolls/.