This final chapter summarizes the substantive findings spelled out in the book. These involved historical changes in phonology, including major sound laws and the appearance and disappearance of two new diphthongs, morphology, primarily involving gender, plurality in nouns and pluractionality in verbs, and the origin of the verb grade system, and syntax, focusing on significant tenses, e.g. the falling together of the aorist and the subjunctive, and in the total revamping of the indirect object system. It ends by raising unanswered questions, such as: did Old Hausa have two fully functional contrastive Rs?; could reflexives originally have been built on the word for ‘body’ rather than ‘head’?; how did the current Completive TAM pronoun paradigm come to be used as subjects?; what accounts for the large number of body part terms that begin with /ha/?; and if the current efferential grade incorporates two distinct and unrelated suffixes, what would their original difference in meaning and function have been?