This article examines how, in a multilingual perspective, language competence is experienced, talked about and practiced by language users themselves. By viewing children as active co-creators of the spaces in which language is used, this article contributes to a research tradition in which focus is shifted from viewing the individual's language competence as a mental linguistic or communicative property, to viewing language as a series of social and spatial practices. Looking at data from the research project "Tegn på Sprog" (in the following referred to as "Signs of Language"), which examines multilingual children's language and literacy acquisition processes, we direct our focus to a single child's active exploration of what it means to know a language. Through analysis of interviews and researcher generated activities, we see how this child both describes and does language competence as a phenomenon that has several meanings, is social, is dependent on location and is unpredictable. Thus, we demonstrate how focus on the child's perspective of what it means to "know language" can lead to insights into the creative, complex and dynamic processes that are part of children's active meaning making with regard to language.