New in paperback. Hardcover was published in 2021. Discourse markers constitute an important part of linguistic communication, and research on this phenomenon has been a thriving field of study over the past three decades. However, a problem that has plagued this research is that these markers exhibit a number of structural characteristics that are hard to interpret based on existing methodologies, such as grammaticalization. This study argues that it is possible to explain such characteristics in a meaningful way. It presents a cross-linguistic survey of the development of discourse markers, their important role in communication, and their relation to the wider context of sociocultural behaviour, with the goal of explaining their similarities and differences across a typologically wide range of languages.