The intention of this article is to explore, challenge and expand our understandings of children's improvised vocalisations, a fundamentally human form of expression. Based on selected examples from observation and recording in non-institutional settings, the article outlines how this phenomenon can be understood as learning and as communication. This is supplemented by suggesting a third possible approach which places these vocal forms within the frame of understanding implied by Foucault's term "technology of the self". This theoretical perspective entails recognising improvised vocalisations as tools used to "act upon the self" in order to attain or reinforce a certain mental state or mood--happiness, satisfaction, anger or longing--in short, as a way in which children learn to know the self as a self. In line with a Foucauldian perspective is also a focus on the negotiation of power and how music serves as an empowering agent in children's everyday social interaction. Finally, informed by Vygotsky's approach to understanding the relationship between language and mental development, the author discusses the gradual disappearance of improvised vocalisations. (Contains 2 figures and 4 videos.)