Sociolinguistics: Introduction

In this lecture, I discuss the following topics about sociolinguistics: *What do sociolinguists study? *What determines language use? *What is variety/code? *What is the meaning of bilingualism? *What is individual bilingualism? *What is societal bilingualism? *What is a first language? *What is a second language? *What is a foreign language? *What is diglossia?