It's easy to say, "use the best language for the job," but actually setting up a project (and a team) to do so can be extremely difficult. Many development teams choose one language to start a project with and end up stuck there forever, despite their intentions. In this talk we'll explore the patterns and practices that make growing a project in a polyglot way both possible and practical. We'll discuss the easiest ways to integrate multiple languages, when to add a new language, and what to do when things feel like they're getting out of hand, all drawn from real world examples.