The Yup'ik, like all Eskimo languages, is a suffixing language made up of noun and verb bases to which one or more postbases and a final ending or enclitics are added to denote such features as number, case, person, and position. The Yup'ik category of number distinguishes singular, plural, and dual. Yup'ik does not have a category of gender and articles. The Yup'ik orthography one sees nowadays was developed at the University of Alaska Fairbanks in the 1960s by native speakers of Yup'ik elders working with linguists. The Yup'ik are the most numerous of the various Alaska Natives. There are 10,400 speakers out of a population of 25,000, and the language is threatened in 2007, according to Alaska Native Language Center. It is a single well-defined language (now called as Yup'ik or Yup'ik and Cup'ik) a dialect continuum with five major dialects: extinct Egegik (Aglegmuit-Tarupiaq), and living Norton Sound or Unaliq-Pastuliq dialect (two subdialects: Unaliq and Kotlik), General Central Yup'ik dialect (seven subdialects: Nelson Island and Stebbins, Nushagak River, Yukon or Lower Yukon, Upper or Middle Kuskokwim, Lake Iliamna, Lower Kuskokwim, and Bristol Bay), Hooper Bay-Chevak dialect (two subdialects: Hooper Bay Yup'ik and Chevak Cup'ik), and Nunivak Cup'ig dialect. Nunivak Island dialect (Cup'ig) is distinct and highly divergent from mainland Yup'ik dialects. Yup'ik was not a written language until the arrival of Europeans, the Russians, around the beginning of the 19th century. Pre-contact knowledge transfer and learning among Yup'ik people traditionally was through oral culture, with no written history or transcribed language. Children were taught about subsistence practices, culture and social systems through stories, legends, toys, and examples of behaviour. The early schools for Alaska Natives were mostly church-run schools of the Russian Orthodox missions in Russian-controlled Alaska (1799–1867), and, after 1890, the Jesuits and Moravians, allowed the use of the Alaska Native languages in instruction in schools. However, in the 1880s, Presbyterian missionary Sheldon Jackson (1834–1909) began a policy of prohibiting Native languages in the mission schools he managed.