Research objectives: this study aims at portraying one of the linguistic/grammar manuscripts that depicts the cultural and educational communications between the lbadhi schools in Oman and the Arab Maghreb. This manuscript is Mushkel E'rab Adda'em, which evolves around the linguistics and grammar of Adda'em written by the Omani scholar Ibn Al-Nadhr Al-Omani. The latter is one of the most widely taught, spread and recited books in the Omani Ibadhi school. This study comes into two sections: documentation and analysis. -Section one comes into two chapters: Chapter one looks into the biography of Sheik Ahmed ibn Al-Nadhr Al-Omani and his book Adda'em. Chapter two looks into the biography of Sheikh Abi Al-Abbas Al-Shammakhi, the author of Mushkel E'rab Adda'em. The second section focuses mainly on Mushkel E'rab Adda'em. This part unfolds into four chapters: -Chapter one deals with the book resources. -Chapter two looks into the evidence, arguments and justifications brought by this book. -Chapter three portrays the choices and selections made in the book. -Chapter four gives a detailed review of the book. -Section three of this study outlines the tools and methods used in the analysis. This section covers five chapters: -Chapter one includes an investigation of the title of the book and it's attribution to its author Abi Al-Abbas Al-Shammakhi. -Chapter two describes the handwritten manuscripts of the book and their locations. -Chapter three outlines the methodology used in studying and analyzing the texts of the manuscript. Chapter four details the symbols/codes used in the study and analysis. Chapter five displays some pictures of the manuscript. The second part shows the texts of the manuscript that this study focused on.