With Crystal, a new language that looks like Ruby but runs like C, it's possible to make phone calls using Twilio. The process involves creating a new Crystal file, making modifications to send HTTP requests and parse responses from Twilio, and then building a simple HTTP server using Kemal to handle incoming webhooks. With Kemal, the framework provides a way to define routes by HTTP verb, which makes it easier to handle complex scenarios like phone calls. By compiling the application in release mode, the performance of the server can be improved even further. The author invites readers to explore Crystal's documentation and source code to learn more about its capabilities.