Modify the Cubetto firmware to speak each command as the program is run.
The Cubetto robot hardware is based on Arduino and its firmware may be modified using the Arduino IDE.
Library suggested by Primo: https://github.com/going-digital/Talkie
The video above says to install support for Genuino Zero (now "Arduino Zero" that the legal battle is resolved between arduino.cc and arduino.org):
Arduino Zero specs:
Microcontroller on Cubetto board says: