Siouan languages
Authors who call the entire family "Siouan" distinguish the two branches as "Western Siouan" and "Eastern Siouan" or as "Siouan-proper" and "Catawban". Others restrict the name "Siouan" to the western branch and use the name "Siouan–Catawban" for the entire family. Generally, however, the name "Siouan" is used without distinction.
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.