Traditional Mongolian Language evolved through the history taking in its purview the Buddha's teaching of the Dharma through the route of the Tibetan language. This research study examined the chronology of the evolution of the Mongolian language and literature, the influence of Tibetan on its grammar and on the written Mongolian. The focus of the study was however on the creation of a written Mongolian language based on the translations of the ten sutras of knowledge of the Tripitaka and the words of foreign origin borrowed from Sanskrit and Tibetan into Mongolian. The findings revealed that the Mongolian grammar, often compared with the content of Sumju, was influenced by the primary grammar of Tibetan and Ogtorgui Maani, the main grammar of written Mongolian. The study also revealed that "Sumdag" which comprised two sutras, Sumju and Dagjug, assisted in the translations of the Buddhist scriptures into Tibetan and Mongolian languages. The "Sumdag" also enriched the Mongolian vocabulary by classification of vowels and consonants; and revived the grammar of ancient texts by developing new grammatical terminology and definitions. This study would provide useful insights to linguists, teachers and students about the influence of "Sumdag" on Traditional Mongolian Language and Dharma Literature.