Shortcut to invoke speech commands

You can make one.

In System Preferences, under Keyboard & Mouse, click on the Keyboard Shortcuts tab. Scroll down to the bottom of the list and click on the Application Keyboard Shortcuts line. Click the + button and fill it in as follows. Application: All Applications, Menu Title: Start Speaking Text, Keyboard Shortcut: press the combination you want to use (shift-control-apple-S for one example, or some other combination you prefer that isn't likely to be used by other apps).

You will need to quit and restart apps before the new shortcut will work.

 

Worked immediately in Safari, Mac OS 10.5.6

Just to confirm, entering "Start Speaking Text" as the menu command does indeed make a functional keyboard shortcut.

Thanks!

 

Go to System Preferences --> Speech --> Text to Speech tab
And check on : Speak selected text when the key is pressed.
Current key is : Option + Esc
You can change key if you want.

Hope it useful.