This document provides an overview of the key concepts and methodological issues covered in the first lecture of a sociolinguistics course. It introduces sociolinguistics as the description of language that takes social context into consideration, and assumes that language and social context influence each other. The lecture covers scope, concepts like accent, dialect, register and social variables like class, gender, age. It also discusses methodological issues in sociolinguistic research like obtaining credible and systematic data through representative samples and the relationship between social and linguistic variables.