Throughout history, Slavic spread from a fairly restricted area somewhere around Ukraine, Belorussia, and Eastern Poland out to large parts of Europe, and Russian as the most widespread Slavic language today spans almost half of the Northern hemisphere. Historic and present migrations of Slavic speakers and the concomitant geographical expansion of their cultural and political dominions could not fail to afford rich opportunities for language contacts of all kinds, running the gamut from mild to intense forms of language contact, from lexical borrowing, language shift, and group bilingualism to the creation of new, contact-induced languages. Language contacts have been part of the history of Slavic from its very outset, and there is virtually no historical period for which no significant contacts can be identified. One of the tasks of this chapter is to give an idea of the deep historical layering of Slavic language contacts from Proto Slavic up to the present age.

Medieval and classical periods in African history are a particular focus of this survey of language contact patterns seen on the African continent. The effects of languages associated with empires and kingdoms are shown to vary widely, with many such languages remaining influential even in the present day. Disentangling earlier patterns of language contact is a necessary step for those interested in reconstructing and classifying African languages. The great time depth and diversity found within each of the major African language phyla is mirrored by a dizzying array of contact patterns both within and across these phyla.