Negesse, Feda (PhD)Negese, Tariku2019-08-292023-11-082019-08-292023-11-082019-07http://etd.aau.edu.et/handle/123456789/18911This study investigated the phonological acquisition of typically growing Oromo speaking children aged 3;0- 5;11 years. For the study, forty-eight children were selected from the western part of its speakers. Since Oromo lacks information about developmental norms, the study intended to describe the order and age at which Oromo sounds are acquired; patterns followed to acquire clusters, syllable shapes employed at different ages, and the types of phonological processes manifested. An experimentation technique was mainly employed for the data collection using an elicitation method. The speech samples were recorded and transcribed using the IPA symbols and conventions. An Optimality Theory was employed to analyze creative alterations at different ages. The findings imply that the acquisition of Oromo phonemes comes about relatively early. At age of 3;0 most of the consonants and all the five vowels were acquired although bilabial stop, some alveolars such as fricative, ejectives, and flap were still developing and are refined after the age of 4;0. Evaluating the children’s accuracy on the basis of sex at the same age, the study revealed no significant difference among males and females. PVC measures are entirely greater than PCC at all ages, for the participants acquired vowels very early. An unusual observation arising from this study was children acquiring the language hardly ever reduced word medial clusters at the age under investigation. They often used a strategy of systematic substitution considering the sounds’ sonority index. Indeed, they select the second member (C2) of the clusters (the consonant making an onset of the subsequent syllable) and replace with (C1) by making some adaptations. The adaptations take two levels of assimilation: complete assimilation at first resulting gemination and reducing the degree of assimilation to partial. Theoretically, this happens when the markedness constraint (CodaConD) outranks faithfulness. In the speech of these children, error patterns arising from their development were mainly sound preference substitution.As to the syllable, children in this sample were able to produce all the language’s syllable shapes and multisyllabic words approximately at three years of age. Normally, the type of speech production patterns noted in the children considered appear to be diversified; most of the patterns are age-appropriate and cross linguistically universal though others are language-specific. For instance, acquisition of most of the phonemes before the age of three is universally accepted even if the acquisition of the languagespecific sound (the implosive) occurred very early, contrary to what is anticipated. In addition, patterns of fronting, backing, devoicing, FCD, and lateralization were similarly regarded as universal patterns marked in the language. However, the pattern of making the process eminent was perceived to be language-specific. Generally, the study findings contributed some points to theories of phonological acquisition and universality hypothesis. Keywords: Oromo, acquisition, phonological processes/simplification, syllable shape, ClusterenOromoacquisitionphonological processes/simplificationsyllable shape, ClusterThesis