This course introduces students to the basic skills of critical thinking and provides a venue to apply these skills to a controversial topic: the emergence of human language. We discuss the following questions: what is language? Do animals have it? How did humans begin to talk? How do children learn to speak? In discussing these questions, we cover the basics of the scientific method and critical thinking. Students practice how to read scientific articles, find their main claims, differentiate between factual and theoretical claims, assess the evidence supporting the factual claims, and critically evaluate the arguments. Students practice small scale data collection, hypothesis formation, and hypothesis testing as part of their final project. We discuss the problems that researchers face in each of these phases of research.