A picture book is the first book in a child's life and therefore has an inestimable value. It is important for the child in stimulating his speech and communication, cognitive, social and emotional development. In the first part of the paper, the picture book, its types and functions in the process of upbringing and education are theoretically treated. Furthermore, in the paper, we consider the picture book as one of the incentives for the speech development of kindergarten and preschool children, the role of educators in the reading process, and the importance of a stimulating environment for the overall development of the child. The backbone of this work is the development of children's speech and picture books in activities, i.e. picture books as an incentive for speech development and vocabulary enrichment. The second part of the paper presents the research that was carried out in DV Didi, in March 2023, in the preschool group, where the children are 5 to 7 years old. We researched the three most frequently read picture books (Little Red Riding Hood, Little Red Riding Hood, Golden Tales 2) in the 2022/2023 pedagogical year, which served as an incentive for children's vocabulary development. The goal of the research was to examine the lexical characteristics of the three most frequently read picture books in the pedagogic year 2022/2023, to examine the lexical diversity and lexical density of the selected picture books, and to examine whether they differ significantly in terms of the lexical characteristics of the selected picture books. The research results show that the Golden Fables picture book contains almost three times more words than the Red Riding Hood picture book and almost twice as many as the Hedgehog's House. In addition to the length of the picture book, we determined through analysis that the picture book Hedgehog's House is the most lexically demanding, while the lexical density of all picture books is approximately similar. Through analysis, we determined the ten most common words in each picture book as well as the ten most common adjectives, verbs and nouns from the said picture books, and we presented the data in tables.