How phonological disorders should be categorized in Turkish children remained vague for a long period of time due to a lack of normative studies. This paper reports the phonological systems of 70 phonologically disordered children, aged 4;0-8;0, in comparison with the results of a normative study of 665 Turkish-speaking children, aged 1;3-8;0. The current focus is on two aspects of development, mainly the differences between disordered and normal consonant acquisition and phonological error patterns from both longitudinal and cross-sectional data. The second concern of the paper is to sub-classify phonological disorders as proposed in the existing literature by examining the applicability of these proposals to Turkish, a typologically different language. It has been indicated that similar developmental trends occur across languages but consonant acquisition is more rapid and developmental errors are more predictable in Turkish. There is evidence for ambient language influence. Mostly, the sub-classifications of phonological disorders are valid for Turkish-speaking children with apparent saliency to language. (Contains 5 tables and 2 figures.)