This study explores the correspondence between Adam Kochański, a Jesuit scholar, and Gottfried Wilhelm Leibniz, a prominent German philosopher, focusing on linguistic studies, China, and Siberia in the second half of the 17th century. During this period, European scholars, particularly those from Protestant German circles, developed a keen interest in linguistic research. Adam Kochański, a renowned mathematician and linguist in the European scholarly community, played a crucial role in linguistic research. Kochański maintained a continuous correspondence with Andreas Müller, a German linguist, from 1675 onwards, focusing on the Chinese language. The study highlights Kochański's involvement in the scholarly endeavors related to linguistic studies, China, and Siberia. Kochański's role as the royal chaplain, librarian, and mathematician to King Jan III Sobieski, as well as his close collaboration with Leibniz, positioned him as a central figure in these investigations. The correspondence with Leibniz, spanning from 1691 to 1698, sheds light on their discussions about the Chinese language, languages of Siberian peoples, and Leibniz's interest in shorthand and the creation of a universal language. The letters provide valuable insights into the intellectual pursuits of the time, the interplay between linguistic studies and religious missions, and the collaborative efforts of European scholars in understanding the languages and cultures of China and Siberia. Kochański's role as a mediator between different scholarly circles and his interactions with Leibniz contribute to a deeper understanding of the intellectual landscape of the late 17th century.