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.
Demographics of Laos
The official and dominant language is Lao, a tonal language of the Tai linguistic group. Midslope and highland Lao speak tribal languages. French, once common in government and commerce, has declined in use, while knowledge of English — the language of the Association of Southeast Asian Nations (ASEAN) — has increased in recent years.