  Child language studies are crucial in improving our understanding of child
well-being; especially in determining the factors that impact happiness, the
sources of anxiety, techniques of emotion regulation, and the mechanisms to
cope with stress. However, much of this research is stymied by the lack of
availability of large child-written texts. We present a new corpus of
child-written text, PoKi, which includes about 62 thousand poems written by
children from grades 1 to 12. PoKi is especially useful in studying child
language because it comes with information about the age of the child authors
(their grade). We analyze the words in PoKi along several emotion dimensions
(valence, arousal, dominance) and discrete emotions (anger, fear, sadness,
joy). We use non-parametric regressions to model developmental differences from
early childhood to late-adolescence. Results show decreases in valence that are
especially pronounced during mid-adolescence, while arousal and dominance
peaked during adolescence. Gender differences in the developmental trajectory
of emotions are also observed. Our results support and extend the current state
of emotion development research.
