eSpeak voice synthesizer on Raspberry Pi

You can turn your Raspberry Pi into an intelligent assistant by using a voice synthesizer like eSpeak. Thanks to this tutorial, you’ll be able to make your robot or application talk.

Hardware

• Raspberry Pi 3 avec Raspberry Pi OS
• Internet connection and remote access

Check Audio devices

First, let’s check the available audio devices

aplay -l

Select audio device

By default, sound is output via the jack or HDMI port. If you wish to connect headphones, you need to select the corresponding output on the Raspberry Pi GUI or with sudo raspi-config.

Check audio

First, we’ll check that the audio is working properly and that the audio peripherals are taken into account.

aplay /usr/share/sounds/alsa/*

Installing the espseak speech synthesizer

sudo apt-get install espeak

To test the espeak installation, simply enter the following command:

espeak "Hello World"

You can also install the python package and use it directly in a script.

sudo apt-get install python3-espeak

from espeak import espeak
espeak.synth("hello world")

To obtain a list of available voices, enter the command

espeak --voices

Using eSpeak in a Python script with Subprocess

You can run shell commands from a Python script using the subprocess library.

from time import sleep
import subprocess

def say(something, voice='fr+f1'):
	print("espeak -v {} {}".format(voice,something))
	subprocess.call(['espeak', '-v%s' % (voice), something])
    
text=[u"bonjour",u"aurevoir",u"a bientot", u"sa va", u"merci"]
textf=u"bienvenu admine, comment allez-vous aujourd'hui?"

for t in text:
	say(t)
	sleep(0.5)

say(textf)

Install pyttsx3

To use the voice synthesizer with Python, we’ll use the pyttsx3 package.

To install the pyttsx3 Python package, enter the following command:

pip3 install pyttsx3

Choose the voice you want

for i,voice in enumerate(voices):
	print("----------------{}".format(i))
	print(voice.id)
	engine.setProperty('voice', voice.id)  # changes the voice
	print(voice.age)
	print(voice.gender)
	print(voice.languages)

Code txt2speech

#!/usr/bin/python3.4
# -*-coding:Utf-8 -*

from time import sleep
import pyttsx3 as pyttsx
engine = pyttsx.init()
voices = engine.getProperty('voices')

print(voices)

engine.setProperty('voice', voices[0].id)  # changes the voice
	
#engine.setProperty('voice', voices[14].id)  # changes the voice
voiceNum=0
#Fr=[0 1 6 7 8 14] #6 = AC
"""
for voice in voices:
	print(voiceNum)
	voiceNum=voiceNum+1
	print(voice.id)
	engine.setProperty('voice', voice.id)  # changes the voice
	print(voice.age)
	print(voice.gender)
	print(voice.languages)
	print(voice.name)
"""

text=[u"bonjour",u"aurevoir",u"a bientot", u"sa va", u"merci"]
textf=u"bienvenu admine, comment allez-vous aujourd'hui?"

#rate = engine.getProperty('rate')
engine.setProperty('rate', 120)

#volume = engine.getProperty('volume')
#engine.setProperty('volume', volume)

for t in text:
	engine.say(t)
	sleep(0.5)

engine.say(textf)


engine.runAndWait()

You should hear your Rapsberry Pi speak!

Add more voices

You can create and add your own voice, taking inspiration from existing voices and reading the documentation carefully. This will enable you to concentrate on certain phrases and pronunciations. Then, once you’ve mastered the settings, you’ll eventually have a voice that suits you.

Improving results with MBROLA votes

You can use another voice synthesizer a little more powerful than eSpeak and install new voices with MBROLA. In our case, we’re installing a French female voice. You can find a suitable voice in the list of available voices.

Check for mbrola. The following command will give you the available voices

apt-cache search mbrola

mkdir espeak
cd espeak
wget https://raspberry-pi.fr/download/espeak/mbrola3.0.1h_armhf.deb -O mbrola.deb
sudo dpkg -i mbrola.deb
rm mbrola.deb

Once you have installed mbrola, you can install new voices

sudo apt-get install mbrola-fr4

espeak -v mb-fr4 "bonjour admin, comment allez-vous?"

N.B.: Pour installer le paquet mbrola, j’ai dû mettre à jour l’OS vers la version 11 (bullseye). Vous pouvez vérifier la version de l’os avec la commande cat /etc/os-release

Obviously, mbrola voices cannot be used with pyttsx3. We therefore use subprocess

from time import sleep
import subprocess

def say(something, voice='mb-fr4'):
	print("espeak -v {} {}".format(voice,something))
	subprocess.call(['espeak', '-v%s' % (voice), something])
    
text=[u"bonjour",u"aurevoir",u"a bientot", u"sa va", u"merci"]
textf=u"bienvenu admine, comment allez-vous aujourd'hui?"

for t in text:
	say(t)
	sleep(0.5)

say(textf)

HMDI audio output

If you wish to use HDMI audio output and there is no sound, it may be necessary to modify the config.txt file

sudo nano /boot/config.txt

Uncomment line hdmi_drive=2

Sources

• PyTTSx3 documentation
• MBROLA voices documentation
• Start with Raspberry Pi