We introduce Wordcraft, a new interactive tablet application that allows children to explore sentence structures and their meanings. Wordcraft uses a constructionist design: children manipulate word cards to build sentences, which come to life in a storybooklike animated world to illustrate meaning. Such visual feedback helps children play with parts of speech and understand how they fit together to form sentences. Preliminary studies suggest that children are able to observe and discuss how different sentence constructs result in different meanings.