Ogiek is a Nilo-Saharan, Satellite-Core, Core, Eastern Sudanic, Southern, Nilotic, Southern, Kalenjin language spoken by a community of Hunters and Gatherers living in the region of the Eastern Escarpement of the Mau Forest in Kenya. In the framework of a still very poorly described linguistic family, this work represents a first, non exhaustive and tentative descriptive grammatical sketch of the dialect spoken by the circa 15.000 Ogiek belonging to the 7 clans of the Morisionig family. The book contains also a short vocabulary of the language, where 646 Ogiek entries are recorded. The vocabulary is completed by a corresponding English-Ogiek wordlist.