This document discusses building natural language interfaces using IBM Watson. It provides an overview of how conversational interfaces work, including using speech recognition to convert speech to text, IBM Watson to understand natural language, and text to speech to generate spoken responses. It also outlines some common applications of conversational interfaces like for customer service, internet of things device control, mobile apps, and more. The document encourages readers to think about how conversational interfaces could simplify interactions with technology in various areas of life.