What language can Grandpa Ji Xianlin speak?

Studying abroad in his early years, he is proficient in English, German, Sanskrit and Pali, can read Russian and French, and is especially good at Northeast Language (an independent language in Indo-European language family, the most widely distributed language family in the contemporary world). He is one of the few scholars in the world who are good at this language. His works have been compiled into the Collected Works of Ji Xianlin, with a total of 24 volumes of * * *, which is "Brahma, Buddhism, and Tam, while China literature, comparative literature, and literary theory are studied in Qi Fei". Before his death, he wrote three titles: master of Chinese studies, academic leader and national treasure.