The development of a child's phonological differentiation in preschool age and at the beginning of compulsory schooling is closely linked to the development of articulation skills and the intelligibility of speech. In the linguistic environment of the Czech and Slovak languages, the presence of developmental deviations in articulation is a frequent and mediatized problem, affecting the development of the success of school education of children at the beginning of schooling. The aim of the presented research was to analyse the state of development of articulation abilities in a representative sample of pupils in the first years of primary school and to verify the effectiveness of the stimulation program for the development of articulation and phonological differentiation.

The research took place in the period 10/2021 - 5/2022, the group consisted of 90 intact pupils (56 boys, 34 girls) of the first grades of primary schools. The pupils were not given a special pedagogical or speech therapy diagnosis and were not included in other stimulation programs. They came from monolingual Slovak-speaking families. Before applying the program, they were examined with a set of diagnostic files, assessing the phonetic-phonological level of language expression, identifying phonological and articulatory deficits. The research group consisted of two subgroups, control (KG) and experimental (EG), each of which had 45 pupils. Both groups were educated in the first grades according to the State Education Program for Basic Education ISCED 1. The experimental group was stimulated by a preventive program through tasks to develop articulation and phonological awareness. The control group was not stimulated by the stimulation program. After the completion of this program, both groups were presented with the same set of diagnostic files as during the initial evaluation of the phonetic-phonological level of language expression. We processed, compared and analysed the results statistically. After completing the preventive program, EG showed significantly better results in articulation, phonological awareness, auditory discrimination.

The results of the research study show that phonological and especially phonemic awareness has an important place in the assessment of pupils' readiness for school, its level can be influenced by the application of a suitable and effective stimulation program, which can be an effective tool for preventing the development of difficulties in the educational process, associated with the development of literacy and intact speech student communication.

Keywords: Articulation, phonological differentiation, stimulation program, beginning of compulsory schooling, speech communication.