Linguistics - the close study of language and languages - is an indispensable foundation for all forms of knowledge. The African continent is blessed with hundreds of languages which act as local repositories of culture and interaction. South Africa alone has eleven official languages, plus Sign Language, many heritage languages, and new languages of global movements and migration. Part of the linguist's business is to document, record and affirm languages and diversity. Applied linguists use their training to understand and enhance the role of language in education and upliftment, and the opportunities and challenges of new technologies of communication. The International Congress of Linguists meets every five years to reflect the development of the field and 2018 is the first time that the congress is being held in Africa. This book is a collection of the plenary and focus papers presented at the conference and thus represents current thinking in the major branches of language study as represented by leading local and international scholars. The papers discuss the history of languages, their structure, acquisition, diversity and use. At the same time due regard is paid to the African continent in connection with its linguistic diversity, multilingualism and educational and societal concerns. The Congress is meant to affirm the value of the languages of Africa, of languages and Linguistics in general, as well as to inspire and equip younger scholars to undertake advanced research into language in its many facets.