This study presents the history of words in the Austronesian languages: how the forms that are attested in the current Austronesian languages developed from the original Proto-Austronesian. A study of this history entails the reconstruction of the sound system (phonology) of Proto-Austronesian, an exposition of the phonological processes that motivated changes, and a presentation of the rules whereby the original sounds changed into those found in the currently spoken languages. The primary aim of this work is to examine exhaustively the forms that can be reconstructed for Proto-Austronesian and also for the earliest stages after the Austronesian languages began to spread southward from Taiwan. The purpose of this study is not just to reconstruct protomorphemes and order the reflexes according to the entries under which they fit, but also to account for the history of each form.