There's a line that looks something like this is /home/pi/start_robot
Note: Before you change anything, backup your start_robot file
cp /home/pi/start_robot /home/pi/backup1_start_robot
Look for a line that's sort of like this:
nohup scripts/repeat_start /usr/local/bin/python3.6 -u controller.py 100 --stream-key WHATEVERYOURKEYIS &> /dev/null &
You can add an option like this to the line:
--voice-number 1
or
--voice-number 2
etc.
You can set --male to make it male (it's female by default)
You can set --pitch to change the pitch (a number between 1 and 100) like --pitch 20
For example (THIS IS ALL ONE LINE):
nohup scripts/repeat_start /usr/local/bin/python3.6 -u controller.py 100 --stream-key WHATEVERYOURKEYIS --voice-number 2 &> /dev/null &