Abstract
The article deals with the level of acquisition of grammatical categories of Czech in a child at age around five years. The author presents the methodology of research mapping the grammatical development of the child from the onset of speech, and the corpus of child language based on one child's audio recordings and diary.
The main focus is on the morphological categories of nouns and verbs. The tendency to regularization and overgeneralization could be observed.
In verbs, the child tries to form regular aspect oppositions, however, it does not always correspond to real usage. The child is able to use complicated structures, such as conditionals and passives.
In nouns, most types of overgeneralizations have already disappeared, there are problems with declension of feminine nouns ending with consonants and words of foreign origin.