in that case its very simple
suppose you are getting 8-bit digital output for different voice commands from your speech module. e.g. 01h for “open” 02h for “close”
so you take this 8-bit output as input to your controller on any one of the port
then you compare the port input with this codes 01h or 02h.
if its 01h rotate motor clockwise and vice versa.
also display the command on LCD when you get 01h or 02h on input port