Pico TTS is in non free, and by default you do not have access to these repositories when you first install Debian. In /etc/apt/sources.list add
after main on all the jessie deb lines.
Now you have to install the TTS library and some audio video tools. Run the following command:
sudo apt-get install libttspico0 libttspico-utils libttspico-data libav-tools
Now find the command line utility to allow you to create sound files from text, or just play them to the sound card. it is here: https://github.com/nano13/nvcli/tree/master/synthDrivers/linux/svox_pico
Download these files, make them executable, and put them in a bin folder in your path.
After you do that then run the different commands and they will tell you what their options are. You can also just read the python script to see what the scripts can do for you.
I went another route and found this first: https://github.com/nano13/nvcli/tree/master/synthDrivers/linux/svox_pico/trash
And downloaded those two files, made them executable, and then used the following script to convert text to an mp3 file.
./pico_read_text_file.py --rate=80% --pitch=110% --audible "false" --output "$1.wav" "$1"
rm -rf "$1.mp3"
avconv -i "$1.wav" -b 96k "$1.mp3"
rm -rf "$1.wav"
The output was far superior to espeak, and is very lifelike. When I was growing up I had a commodore 64 and we had an 8kb voice synthesizer called SAM. So to see the progress in just a couple of decades is amazing to me.
This would be awesome if I can get it to run on Raspberry Pi computers. http://rpihome.blogspot.com/2015/02/installing-pico-tts.html