All levels of language analysis are prone to changes in their phonology, morphology, graphology, lexis, semantics and syntax over the years. Tiv language is not an exception to this claim. This study investigates various aspects of phonological or sound changes in Tiv language. This paper therefore classifies sound changes in Tiv; states causes of sound changes in Tiv and explores implications of sound changes. The research design used in this paper is purposive sampling of relevant data. The instrument used in this paper is the observation method in which the author selected words that showed epenthesis, deletion and substitution. It has been noted that the use of archaic spellings in the Modern Tiv literatures shows their ancientness. Phonological change is not a deviation but a sign of language growth and changes in spellings result in changes in sounds. The author recommends that scholars should write papers or critical works on lexical/morphological, syntactic, semantic, graphological changes in Tiv language. Students should write projects, dissertations and theses on language change and diachronic linguistics. This study introduces Tiv historical linguistics and diachronic phonology which serve as catalysts for the study of Tiv language. The understanding of Tiv sound change provides students with a much better understanding of Tiv phonological system in general, of how Tiv phonology works and how the phonemes fit together