Toggle Text-to-Speech - Command T Pause or resume reading - Space bar (while in a book) Read the current sentence - Command S. Press Command Tor select the Toolsmenu and choose Start Text-to-Speech.
To use these shortcuts, you must enable Text-to-Speech first. Text-to-Speech is only supported with Mac OSX 10.10 or above. This is a great trick because it allows you to quickly speak what is in on the Mac screen like a document, PDF file, ebook, or web page, and all it takes is a keyboard shortcut to speak the text that is selected or in the active document.