Our maps are based on fieldwork carried out by undergraduate students of Linguistics and English Language at the University of Manchester.
As part of their coursework for the module Language Variation and Change, these students investigate the linguistic diversity present in British English by asking their friends and family to complete a questionnaire. You can see a sample questionnaire here.
Over 5000 English speakers have participated in our study. They range in age from 10 to 89 and span a geographical region from Lewis to Cornwall.
Laurel MacKenzie, George Bailey, and Danielle Turton gave a presentation on the maps at Methods in Dialectology XV in Groningen, Netherlands. You can see the slides here, which give more information about how the maps were made.