 They are not mutually intelligible, even though many works often refer to all of the speakers of these languages as "Maidu".The Chico dialects are little known due to scanty documentation, so their precise genetic relationship to the other languages probably cannot be determined (Mithun 1999), and in any case may have been not a fourth Maiduan language, but widely divergent dialects of Konkow (Ultan 1967).Three of the languages went extinct by approximately the year 2000.