Siouan languages
Siouan languages can be grouped into the Western Siouan languages and Catawban languages. The Western Siouan languages can be divided into Missouri River languages (such as Crow and Hidatsa), Mandan, Mississippi River languages (such as Dakotan, Chiwere-Winnebago, and Dhegihan languages), and Ohio Valley Siouan branches. The Catawban languages consist only of Catawban and Woccon.
Sikaiana language
The people of Sikaiana speak the Sikaiana language or Central Solomon Pidgin English. After WWII, many people from Sikaiana migrated to Honiara, the capital of the Solomon Islands in search of jobs and education (Donner, 2002). This means that there was a decrease in the use of the language, since Sikaiana was not the language mainly used in that area. A decrease in the advantages of using the Sikaiana language increases the endangerment of it.