The Speech Synthesis Manager, formerly called the Speech Manager, is the part of the Mac OS that provides a standardized method for Mac apps to generate synthesized speech. For example, you may want your application to incorporate the capability to speak its dialog box messages to the user. A word-processing application might use the Speech Synthesis Manager to implement a command that speaks a selected section of a document to the user. Because sound samples can take up large amounts of room on disk, using text in place of sampled sound is extremely efficient. For example, a multimedia application might use the Speech Synthesis Manager to provide a narration of a QuickTime movie instead of including sampled-sound data on a movie track.
OS X v10.5 introduces native support for performing speech synthesis tasks using Core Foundation-based objects, such as speaking text represented as
CFString objects and managing speech channel properties using a
CFDictionary-based property dictionary. You should begin using these Core Foundation-based programming interfaces as soon as it’s convenient, because future synthesizers will accept Core Foundation strings and data structures directly through the speech synthesis framework. In the meantime, existing buffer-based clients and synthesizers will continue to work as before, with strings and other data structures getting automatically converted as necessary.
You can check for version and feature availability information by using the Speech Synthesis Manager selectors defined in the Gestalt Manager. For more information see Inside macOS: Gestalt Manager Reference.