Macro-Siouan languages
In the 19th century, Robert Latham suggested that the Siouan languages are related to the Caddoan and Iroquoian languages. In 1931, Louis Allen presented the first list of systematic correspondences between a set of 25 lexical items in Siouan and Iroquoian. In the 1960s and 1970s, Wallace Chafe further explored the link between Siouan and Caddoan languages. In the 1990s, Marianne Mithun compared the morphology and syntax of all the three families. At present, the Macro-Siouan hypothesis based on relations among Siouan, Caddoan, and Iroquoian is not universally accepted as proven.
Siraya language
Several Siraya communities have been involved in a Sirayan cultural and language revitalization movement for more than a decade. Through linguistic research and language teaching, the natives are 'awaking' their mother tongue that has been 'dormant' for a century. Today a group of Siraya children in Xinhua District of Tainan particularly in Kou-pei and Chiou Chen Lin area are able to speak and sing in the Siraya language.