Isogloss: When linguists create maps showing where dialects are spoken, the isoglosses would be the boundary lines they draw. These isoglosses chart where a particular linguistic feature appears or does not appear. For instance, the use of the second person plural 'y'all' might be mapped in the American south, and the second person plural 'youse' might be mapped around the Bronx and New Jersey. These dialect boundaries would be different isoglosses on the map.