1. A playback control apparatus comprising: circuitry configured to control continuous playback of a user-defined program including first, second, and third content, the first content including first sound which is generated based on text information received from a first source using speech synthesis processing, the second content including second sound which is generated based on text information received from a second source different from the first source using the speech synthesis processing, and the third content including third sound which is not generated using the speech synthesis processing, wherein the circuitry displays an attribute of content to be played back, the attribute indicating whether or not the content includes sound which is generated based on text information using speech synthesis processing.