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.
Austroasiatic languages
This is identical to earlier reconstructions except for . is better preserved in the Katuic languages, which Sidwell has specialized in. Sidwell (2011) suggests that the likely homeland of Austroasiatic is the middle Mekong, in the area of the Bahnaric and Katuic languages (approximately where modern Laos, Thailand, and Cambodia come together), and that the family is not as old as frequently assumed, dating to perhaps 2000 BCE. Peiros (2011) criticized Sidwell's theory heavily and calls it a bunch of contradictions. He show with his analysis that the homeland of Austroasiatic is somewhere near the Yangtze. He suggests the Sichuan Basin as likely homeland of proto-Austroasiatic before they migrated to other parts of central and southern China and than into Southeast Asia. He further suggests that the family must be as old as proto-Austronesian and proto-Sinotibetan or even older.