This document discusses several external and regional patterns that influence linguistic variation, including social class, gender, age, urbanization, migration, and social networks. It examines how variables like postvocalic /r/, the use of /ing/, and /h/ dropping patterns vary based on social factors. Style and formality of speech, as well as the influence of gender and age are also covered. The role of social networks and processes like standardization that can promote linguistic uniformity are summarized.