The Ndebele of Zimbabwe speak a Zulu-Ntungwa dialect which they call isiNdebele though the language is not close to the Ndebele languages of the Republic of South Africa. However, the difference between the isiNdebele language of Zimbabwe and Zulu language of South Africa is not much.
The two languages are mutually intelligible to some degree, with differences in pronunciation, accents, and some loan words. The Ndebele culture and language of Zimbabwe are similar to Zulu culture, as they share ancestry and common origins with Zulu people from the KwaZulu Natal (KZN) province of South Africa.
The history of the Ndebele of Zimbabwe began when a Nguni group split from King Shaka in the early 19th century under the leadership of Mzilikazi, a former chief in his kingdom and an ally. The isiNdebele of Zimbabwe also has close affinity to other Nguni languages like isiXhosa and SiSwati. On other hand, the Northern Ndebele are a Mbo ethnic group native to South Africa who are an offshoot of the Southern Ndebele and they are concentrated in the Limpopo and Northwest provinces of South Africa.
Within the borders of the Republic of South Africa, there are two ethnolinguistic groups divided into Northern Ndebele and Southern Ndebele who speak different but related Ndebele languages, namely siNdrebele (Northern Ndebele) and isiNdebele (Southern Ndebele). The Northern Ndebele tribes in South Africa are constituted by Mghumbhani (Mokopane), Mtjhatjhani (Mashashane), Gheghana (Kekana) and Langa (amaNdebele ka Langa), whereas the Southern Ndebele comprise the Ndzundza and Manala tribes. (source: online sources)