Notes on Mangue: An Extinct Dialect Formerly Spoken in Nicaragua is a unique book written by Daniel J. Brinton that reveals the mysterious Mangue language that once existed in Nicaragua. Interwoven with the content of the book are both academic research and the scientist's personal recollections of the quest to understand this long-extinct language. The author reveals in detail the history of Mangue, its grammar and vocabulary, trying to revive the ancient language through his research. The book "Notes on Mangue" captivates the reader with its interesting information about the linguistic diversity and cultural heritage of Nicaragua.