It is not unusual, of course, for children of Ellaâ€™s age to have imaginary friends or siblings. The creation of an imaginary character is related, I believe, to the explosion of linguistic abilities that occurs between the ages of two and four, and rapidly creates an excess of language, which the child may not have enough experience to match. She has to construct imaginary narratives in order to try out the words that she suddenly possesses. Ella now knew the word â€œCalifornia,â€ for instance, but she had no experience that was in any way related to it; nor could she conceptualize it in its abstract aspectâ€”in its California-ness. Hence, her imaginary brother had to be deployed to the sunny state, which allowed Ella to talk at length as if she knew California. The words demanded the story.