Project Washoe and its sequel with Moja, Pili, Tafu, and Dar, simulated with infant chimpanzees the conditions in which the language of human children develops gradually and-piecemeal into the language of human parents. This article traces patterns of growth and development in the early utterances of children and chimpanzees. The evidence for continuous processes and variables contradicts the yes-no, either-or Aristotelian logic of philosophical linguistics that has prevailed for so long. What the children and chimpanzees actually say supports, instead, a view of common laws and continuity that is much more compatible with modern natural science.