Many people have spent their lives in search of language origin and have made great efforts to discover which language is the mother of all other languages (Mother language). As their efforts were not rightly directed, they could not achieve success. Thus, this paper examines the origin of Afaan Oromo and its impact on theories of languages and language origin. In the area of language and language origin, this paper argued that Afaan Oromo has unique properties to offer the field, or at least the richness that is provided by the majority of words creation offers basic and unusual opportunities for theoretically-minded theories. In both cases what we have learned from Afaan Oromo has provided us major insight into the nature of language origin and mother language. No wonder, ‘One of the best-kept secrets of the Afaan Oromo is the predictability, clarity, source imitating and/or conceptually approximating nature and rules of roots and its verb inflections’. Afaan Oromo is purely natural nature based language. Each and every roots of Afaan Oromo were created from either corresponding Sounds or available roots and thus, converges to sounds proximate to it. Verbs, nouns and new roots were created from available related sound imitating roots and so and so on again and again. Thus, Oromo followed up the idea and elaborated language. According to this paper language is, not a fully developed faculty in people, acquired by human gradually on day to day 5S (Sense, Sort, Set, Schematize and Speak) acquisition process. The author’s propose that it was a gradual phenomenon that new roots possessed from new sound sensed and derivations were done as human thought progressed. The perception of community in interpretation and creation of meaning and relationship between the roots and sounds corresponding (sound root imitates) alone explains language origin. Afaan Oromo, mother language of human being, has the most natural sound imitating roots. Other languages have fewer natur