Can you disable the voice in speech central? Help would be greatly appreciated

Hello everyone,
First, thank you in advance for taking the time to read this post and for offering up suggestions.
I am currently reading an EPUB ebook for a paper that I'm writing for class, and I have been using speech central to read it, as it seems this is the best app out there to read pubs more accessibly on the Mac. While I enjoy the voice reading the books to me in the background, there are times I need to turn off the voice, and just read the text with voiceover, so I can analyze it more clearly, and when necessary, spell things correctly should I need to incorporate a key term or quote into my paper. I am able to navigate around in the text area of the book with speech central, but each time I do, I hear the voice on top of my voice over voice, and she just keeps going, not allowing me to stop and navigate in more shorter elements like characters and words. If I use the stop command to stop her from reading the book, she does stop reading, but closes the book. I need to be able to keep the book open to read the text, but without the interference of her voice, sort of like with voice dream, where you have the play/pause buttons to start/stop the voice whenever necessary, but are still able to navigate the text area with voice over. Is there a command to temporarily turn off the voice in speech central, but still be able to read the book? If not, is there a way I can use another app that will allow me to interact with the text of the book? Your help will be greatly appreciated.
Thank you.