"Des variations du langage français depuis le XIIe siècle" by F. Génin is a scholarly treatise written in the mid-19th century. The work explores the evolution of the French language, specifically focusing on orthography and pronunciation changes throughout history. It delves into linguistic nuances and attempts to establish principles that can govern the writing of the French language. The opening of the book presents the author's argument against the perception of the old French language as barbaric, a view espoused by figures like Voltaire. Génin asserts that understanding the historical context and pronunciation of ancient French can offer insights into the complexities of modern French orthography. He emphasizes the importance of appreciating the language's roots, advocating for a study of its evolution rather than dismissing the past in favor of the present. Through a combination of critical analysis and historical anecdotes, Génin sets the stage for a broader examination of how changes in pronunciation, orthography, and influences from other languages have shaped contemporary French dialects and practices.