How to Disable Speed Dial?
While this solution does not disable speed dial it does make the phone less sensitive to pauses, and makes dialing when talk back and explore by touch are both active much friendlier.

Suggestion by a family friend, worked great thank you. 

Settings > Language &amp; Input > Pointer Speed 

Adjust the slide setting by touching the end of the slide (does not slide on our phone when talk back and explore by touch are both active.  

On our phone, sliding to right (100%) significantly decreased the number of times the speed dial dialog box popped up.