The concept of linguistic relativity (or Whorfianism) has its roots in the linguistic anthropology of Edward Sapir and his student Benjamin Whorf in the early twentieth century. However, questions over the relationship between natural language and human cognition go much further and deeper. Unfortunately, linguistic relativity has about as many misinterpretations as it does labels (linguistic relativity, linguistic relativism, linguistic determinism, Whorfianism, Sapir-Whorf hypothesis - weak and strong). The idea that language determines thought through an environmentally constrained feedback system is at the heart of most concepts associated with linguistic relativity. The real philosophical questions, however, only seem to present themselves at a level beyond the trivial truism that linguistic structure has an effect on thought, i.e. different languages might encode environmental information differently resulting in variation in things like processing times, measured in psycholinguistic experiments. These questions are important for a number of related disciplines, yet the concept itself is one of the most misunderstood in modern anthropology, sociology, philosophy of language, linguistics, and cognitive science. This book contributes much needed clarity to a theoretical landscape at the centre of insights into what makes us human, both linguistically and cognitively.