Text to speak software with espeak and mbrola. Test on Raspberry Pi2 (Raspbian/jessie) and Pi4 (Raspbian/buster).

say_cpu_temp.py

#!/usr/bin/env python3

import os, time
 
while True:
    with open('/sys/class/thermal/thermal_zone0/temp', 'r') as f:
        cpu_temp = round(float(f.read()) / 1000)
    os.system('espeak -v mb-fr1 -s 95 \'La température de la CPU est de %s degrés.\'' % cpu_temp)
    time.sleep(2.0)

setup_rpi2_jessie.sh

# setup script for Raspberry Pi2 (Raspbian/jessie)

# install espeak
sudo apt-get install espeak

# install mbrola
wget http://tcts.fpms.ac.be/synthesis/mbrola/bin/raspberri_pi/mbrola.tgz
tar xvzf mbrola.tgz 
chmod 755 mbrola
sudo mv ./mbrola /usr/local/bin/

# install voices for mbrola
wget http://tcts.fpms.ac.be/synthesis/mbrola/dba/fr1/fr1-990204.zip
sudo unzip fr1-990204.zip -d /opt/mbrola
sudo mkdir -p /usr/share/mbrola/voices/
sudo cp -r /opt/mbrola/fr1/* /usr/share/mbrola/voices/

# test it !
espeak -s 125 -v mb/mb-fr1 'installation terminé. On peux maintenant utiliser espeak !'

# sample script  for use with python

# #!/usr/bin/env python
# # -*- coding: utf-8 -*-
# 
# import os, time
# 
# var1 = 0
# 
# while True:
#     os.system('espeak -v mb-fr1 -s 120 \'variable var1 égale à %s\'' % var1)
#     var1 += 1
#     time.sleep(1.0)

setup_rpi4_buster.sh

# setup script for Raspberry Pi4 (Raspbian/buster)

# install espeak (will be replace by espeak-ng see https://github.com/espeak-ng/espeak-ng)
sudo apt-get install espeak

# install mbrola (binaries of debian "non-free" category are not available on Raspbian/buster)   
wget http://ftp.fr.debian.org/debian/pool/contrib/m/mbrola/mbrola_3.3+dfsg-4~bpo10+1_armhf.deb
sudo dpkg -i mbrola_3.3+dfsg-4~bpo10+1_armhf.deb
rm mbrola_3.3+dfsg-4~bpo10+1_armhf.deb

# install voices for mbrola ("non-free" but as it's not binaries packages we can install it)
sudo apt-get install mbrola-fr1 mbrola-fr2

# test it !
espeak -s 95 -v mb/mb-fr1 'installation terminé. On peux maintenant utiliser espeak !'

# see say_cpu_temp.py sample script for an example of use with python3