John and Ken begin the show by illustrating how multifaceted and nuanced language in action can be by proceeding through a number of miscommunications and confusions arising from everyday language use. Ken distinguishes between semantics, syntax, and pragmatics.

Ken introduces Dan Sperber, a social and cognitive scientists who published a landmark work in pragmatics, "Relevance: Communication and Cognition." John mentions that before Sperber's work, most language comprehension was thought to originate in words, with a little bit of intention-guessing being important, while after Sperber's work most of language seems based on intention. Dan Sperber discusses these two positions and points out the banality and simplicity of implication in normal speech. How is it that we understand each other so well with so few words? If we don't encode our meaning through words, how do we represent meaning in our minds? Are these cases of implicature just shortcuts or do they speak to something deeper about the nature of language? Ken and John ask Daniel Sperber about these topics, and he describes a middle ground between many of these options.

Dan Sperber goes on to describe the Grice's idea of conversational implicature and the vast amount of information that is conveyed in successful communication which is not contained in the individual words used. The use of implicit meaning is the core topic of pragmatics, and John compares Grice's maxims for understanding this type of meaning with Sperber's theory. Ken returns to the banality of implicit meaning and Dan and Ken discuss the intricacies of the simple word "and" in the English language. Ken wonders why instead of dealing with messy things like speaker intention we can't just give many definitions for each words. Furthermore, how is it possible for us to understand so much intention, don't we have to be mind readers to simply communicate if so much of our language is implicit?

John, Ken, and Dan discuss callers' ideas about language and communication, relating stories about communication and miscommunication, surprising anecdotes about people understanding things without language, and analysis of the amazing way we all communicate with and without words.

• Roving Philosophical Report (Seek to 4:18): Polly Stryker channels the notorious Mae West to investigate some of the more subtle sides of language use.

• 60-Second Philosopher (Seek to 49:54): Ian Shoales does a rapid-fire history lesson on rhetoric and types of speech which were once widely taught and now are mostly forgotten.