This book is a linguistic study of Jahai, a language belonging to the Northern Aslian subgroup of the Aslian branch of the Mon-Khmer language family. The language is spoken by groups of foragers in the mountain rainforests of northern Peninsular Malaysia and southernmost Thailand, its total number of speakers estimated at around 1,000. This study describes the grammar of Jahai, including its phonology, processes of word formation, word classes, and syntax. It also includes a word-list. While primarily aimed at linguistic description, the study makes use of suitable theoretical models for the analysis of linguistic features. In particular, models of Prosodic and Template Morphology are employed to describe the language's intricate processes ...