The twenty Central Plateau languages are a residual branch of the Plateau family spoken in central Nigeria. Tyap, or Katab, has 130 000 speakers, and the closely related Jju AKA Kaje has well over 300,000. Hyam, or Jabba, has another 100,000. Cori is famous for being one of very few languages with six tone levels, though only three are needed for writing.