My homage to Person of Interest's Harold Finch:
The code uses Python OpenCV alongside Python SpeechRecognition 3.1.3, to achieve face detection by speech input.
To install SpeechRecognition 3.1.3 on your linux system, type the following commands:
sudo apt-get install python-pyaudio python3-pyaudio
sudo apt-get install python-pip
sudo pip install SpeechRecognition