Applying network theory to fables: complexity in Slovene belles-lettres for different age groups

Words are the building blocks of human communication. They are arranged in sentences in a non-trivial and universal way, which implies the existence of fundamental organizational principles that have shaped language development. One of the fundamental examples is the Zipf's law, which says that the frequency of word occurrence is roughly an inverse power-law function of its rank. In our article, we study the structure and complexity of texts in Slovene belles-lettres, with an emphasis on evaluating the differences in the texts for different age groups. We show that the co-occurrence connectivity of words forms a complex and heterogeneous network that is characterized by an efficient transfer of information. Moreover, we show that with the increasing age of readers, the length of texts, the average length of words, different combinations of phrases and the complexity of social interactions between literary characters, also all increase. Conversely, the fraction of unique words decreases. We also show that the word co-occurrence networks for older age groups are less modular and exhibit a higher level of small-worldness, and that the Zipf's exponent as a measure for the linguistic complexity is more negative, than for younger age groups. Taken together, we demonstrate that network theory enables an in-depth theoretical exploration of Slovene belles-lettres, with clear distinctions in statistical properties between different age groups, thus bridging art and exact sciences in a mutually rewarding way.