The book presents Hausa reduplication in the light of grammaticalization and lexicalization processes. Hausa is a Chadic language of Afro-Asiatic family that is very rich in patterns of reduplication, and extensively uses reduplication in grammatical structures and lexical formatives. The connection between these interrelated parts may be interpreted through systems interactions in the coding of functional domains. The model of functional domains allows connecting the two opposite pathways of language change, i.e. grammaticalization and lexicalization, and discussing the process of reduplication in terms of principle for explaining language structure. This book is meant to contribute to studies on reduplication in Hausa and other languages in terms of its forms and functions and to be an inspiration for investigating the topic of reduplication from the perspective of communication.