By comparing the spontaneous speech of two-year-olds and their parents, we can determine whether, and to what degree, their grammars differ. This talk uses two case studies to argue that two-year-olds and their parents have the same basic grammar. Children are similar to their parents, without directly copying their parents. Children differ from parents in executive functions (like planning and updating) more than in grammar. With respect to basic grammar, I argue that nothing develops. What develops is vocabulary and executive function.