In Read Aloud books, an audio file using a narrator’s voice can read the text on a page and the words can be highlighted as they are spoken. The reader can choose to have the pages turn automatically to keep the session flowing, or set them to turn manually. A tap on the screen displays controls in the upper-right corner of the book to customize the reading and listening experience. Note that read aloud content is supported only in fixed-layout books. Apple Books syncs text and audio using Media Overlays, an EPUB-specific subset of Synchronized Multimedia Integration Language (SMIL). This section provides information about Media Overlays, SMIL files, and tips for using Media Overlays to create Apple Books read aloud content.
Read Aloud books require a custom preview. See Samples for Read Aloud Books.