This thesis explores the evolution plural verbal -s ("People thinks he is guilty") and zero 3rd singular ("He think he is guilty") in data from two sources on Southern English: The Linguistic Atlas of the Gulf States (LAGS) and The Linguistic Atlas of the Middle and South Atlantic States (LAMSAS). The research questions that underlie this study consider (1) the demographic association of plural verbal -s and zero 3rd singular, (2) the maintenance of each form, (3) the constraints on their use, and (4) the origins of -s variability. The atlas data suggest the following for plural verbal -s: (1) it has a British source, (2) it was present in both African American Vernacular English (AAVE) and early Southern White English (SWE), and (3) there were different grammatical constraints on its use in AAVE and SWE. Data for zero 3rd singular -s suggest this form (1) did not have a British source and (2) that it has historically been an AAVE feature.