With a little clicking and a lot of scrolling you can add any command to the Word Quick Access Bar.
The best solution in these situations is to too add the command for the feature you are looking to use to the Word Quick Access Bar.
Note: the screenshots in this article are from Office 2010, but they could just have well been from Office 2013 - the steps are the same for any ribbon-based version.
Quick Access Bar
The steps are not difficult, but there is likely to be a bit of scrolling. First, start Word, left-click the Quick Access Bar options button (it's the down arrow), and then click the More Commands item. (Figure A)
Click the dropdown arrow under the Choose commands from section and change the selection to read Commands not in the Ribbon. Scroll down the list until you find Speak, as shown in Figure B.
Click Speak and then click the Add button to add it to your Quick Access Bar, as shown in Figure C. Click OK when you are done.
While you are viewing the list you might want to add other features that are not listed in any Ribbons. This process will work for any command.
As you can see in Figure D, there is now a speak button on my Word Quick Access Bar.