Today many of the tribes continue to officially call themselves "Sioux". In the 19th and 20th centuries, this was the name which the US government applied to all Dakota/Lakota people. However, some tribes have formally or informally adopted traditional names: the Rosebud Sioux Tribe is also known as the Sičháŋǧu Oyáte (Brulé Nation), and the Oglala often use the name Oglála Lakȟóta Oyáte, rather than the English "Oglala Sioux Tribe" or OST. (The alternate English spelling of Ogallala is deprecated, even though it is closer to the correct pronunciation.) The Lakota have names for their own subdivisions. The Lakota also are Western of the three Sioux groups, occupying lands in both North and South Dakota.