The paper presents an analysis of the phonological features of preschool children. The article aims to find patterns of typical and atypical errors. A method was created to conduct the study, which includes three levels of research - at the level of words, sentence repetition, and generating one's speech by picture (spontaneous speech). The results show that children's most common phonological errors are as follows: sound substitution, elision of sound, metathesis of sound, elision of syllable, and deletion of consonants clustered in a syllable. The data obtained from the noun generation task was informative enough about the phonological development of the children being studied. The repeated speech task was accessible for the children and of little value in analyzing the phonological processes. The sentence generation task provides sufficient information about sentence structure, prosody, rate, and force of speech. The test serves a diagnostic and therapeutic purpose. The diagnostic analysis is clear and informative enough to create a therapeutic program based on the examination results. Subsequently, it could be applied for re-testing to measure the progress in the child's output. In addition, the average time children take to administer the whole test is less than 18 minutes, which is an additional positive aspect of the test. The ultimate goal is to standardize this test to assist clinicians in establishing norms by examining Bulgarian-speaking children and assessing their phonological development.