In a number of languages, the reduplicant tends to be unmarked or less marked than the base which it copies although the language in question may have marked prosodic and segmental structures outside reduplication. Traditional rule-based derivational approach failed to account for the cross-linguistic emergence of the unmarked phonological structures because of ordering paradoxes while templatic approach equally failed to explain the variation in their ‘templates’. Currently, this is explained in terms of the ‘The emergence of the Unmarked’ (hereafter, TETU) in Optimality Theory (OT). This paper argues that the emergence of the unmarked phonological structures is best captured in terms of constraints, which though dominated, may emerge to favour structures that are unmarked over those which are marked. Based on Lubukusu (Bantu, Kenya) reduplication, it is shown that constraints against onsetless syllables and monosyllabic stems (though dominated in the constraint hierarchy of the language), are responsible for the unmarked CV syllables and bisyllabic prosodic words. At the segmental level, it is shown that the unmarked and preferred epenthetic segments are coronals while the Bantu verb final vowel [a] is considered unmarked in this position. This is done through constraint interaction without stipulating any derivational rules or templatic specifications. The study proposes that the universal TETU ranking is sufficient in accounting for this phenomenon across languages.