This study investigates the linguistic relationship between Southern and Northern Ndebele. The focus is on the historical background of the two main South African Ndebele groups, covering various linguistic aspects, such as phonology, morphology, lexicography and spelling rules. The research reveals that, despite the fact that Southern and Northern Ndebele share a common name and historical background, the death of the Ndebele ancestral chief, Musi, at KwaMnyamana, which caused this nation to split into Southern and Northern Ndebele, resulted in the two Ndebele languages. As this study shows, these differ substantially from each other. The two Ndebele languages are examined, phonologically, in Chapters Three and Four revealing demonstrable phonological differences. Southern Ndebele, for instance, has several sounds (e.g., click sounds) that do not occur in its northern counterpart, while Northern Ndebele contains a number of non-Nguni sounds (e.g., interdentals) that do not occur in Southern Ndebele. Phonologically, Southern Ndebele, like other Zunda Nguni languages, employs the voiced lateral alveolar fricative phoneme /z/ [z] (e.g., izifo ‘diseases’), whereas Northern Ndebele, like other Tekela Nguni languages, uses the ejective interdental explosive /t/ [t’] (e.g., tifo ‘diseases’). Morphophonologicallly, the so-called denasalition feature that both languages manifest in their primary and secondary nasal compounds (i.e., Classes 9 and 10 noun class prefixes) occurs in almost opposing ways. In Southern Ndebele, the nasal /n/ resurfaces in all noun class prefixes of Class 10 nouns, while in Northern Ndebele, it occurs only in the noun class prefixes with monosyllabic stems or stems beginning with a voiced or semi-voiced consonant. This morphophonological feature (denasalisation) has spread to other grammatical environments, such as adjectival concords, inclusive quantitative pronouns and all formatives with the nasal compound ng [g] , in Northern Ndebele. The two languages also reveal that there are differences in assimilation, syllabification, palatalization, vowel elision, vowel substitution, consonantalization, glide insertion and labialization. Chapters Five to Eight focus on morphological differences. Here, the two Ndebele languages show differences in the various word categories: nouns, pronouns, qualificatives, copulatives, adverbs, moods, tenses, verbs, auxiliary verbs, conjunctives and ideophones. For instance, whereas Southern Ndebele noun class prefixes, like other Nguni languages – such as isiZulu and isiXhosa – comprises the pre-prefix + basic prefix + stem (e.g., u-mu-ntu ‘person’ a-ba-ntu ‘people’), in Northern Ndebele, this word category comprises the basic prefix + stem like Sotho languages (e.g., mu-nru ‘person’ ba-nru ‘people’). In addition, while the noun class prefix of Class 8 in Southern Ndebele contains a nasal before polysyllabic noun stems (e.g., iinkhova ‘owls’), in Northern Ndebele, Class 8 noun class prefixes contain no nasal (e.g., tikxabula ‘shoe’). Lexically, the most salient differences are that, although the two Ndebele languages share similar Nguni vocabulary, they have been unequally influenced by the neighbouring Sotho languages. Most importantly, despite the fact that both Ndebele languages have borrowed words from Northern Sotho and Setswana, Northern Ndebele has borrowed many more terms than Southern Ndebele. Lastly, in line with the Southern Ndebele (2008) and Northern Ndebele (2001) Spelling Rules, this investigation observes that the two Ndebele languages differ radically. In Southern Ndebele, for instance, there are numerous language aspects that have spelling rules governing their encryption, but in Northern Ndebele no rules exist as yet for such aspects. The findings reveal that Southern and Northern can be regarded as two distinct languages that deserve autonomous development even though they trace their origin from the same historical source.