Tumbuka is a Bantu language spoken by about 2 million in northern and central Malawi, and the Lundazi District of Zambia. The Tumbuka spoken in urban areas differs significantly from that spoken in rural areas, which is considered by some as the 'real Tumbuka'.
Tumbuka has no official status in either Malawi or Zambia. It is used to some extent in literature in Zambia, but in Malawi the only Tumbuka literature permitted is religous material.
source
wikipedia.org,
omniglot.com &
ethnologue.com