This book is based on a typological/functional perspective which provides an excellent framework for writing a broadly useful, descriptive grammar. Retuara, is also kw as Letuama (Tanimuca-Retuara, Retuama, Letuhama, Ufaina, Uaira) is a member of the central Tucaan language family and is closely related to Tanimuca. Though the Retuara and Tanimuca peoples consider themselves as separate groups, they speak the same language with slight lexical differences. Their location is in widely distributed areas of the Amazon Basin in southeastern Colombia has brought them into contact with other Tucaan and Arawakan languages resulting in some grammatical variations. Besides a brief phological sketch and description of various aspects of the Retuara language, the study presents a detailed discussion of parts of the speech, the un phrases, case, the verb phrase, adverbs, sentence structure, imperatives, questions, negation, subordination, and various elements of discourse.