structural:summarization, structural:scholar_edition, linguistic:voice_change
Indo-European

August Conrad proposed the Sino-Tibetan-Indo-European language family. This hypothesis holds that there is a genetic relationship between the Sino-Tibetan language family and the Indo-European language family. The earliest comparative linguistic study of Chinese and Indo-European languages was by the 18th-century Nordic scholar Olaus Rudbeck. He compared the vocabulary of Gothic and Chinese and guessed that the two may be of the same origin. In the second half of the 19th century, Kong Haogu, Shigude, Ijosser, etc. successively proposed that Chinese and European languages are homologous. Among them, Kong Haogu, through the comparison of Chinese and Indo-European domestic animal vocabulary, first proposed an Indo-Chinese language macrofamily (including Chinese, Tibetan, Burmese, and Indo-European languages).

In the 20th century, R. Shafer put forward the conjecture of a Eurasial language super-family and listed hundreds of similar words between Tibeto-Burman and Indo-European languages.