Using pyttsx

An application invokes the pyttsx.init() factory function to get a reference to a pyttsx.Engine instance. During construction, the engine initializes a pyttsx.driver.DriverProxy object responsible for loading a speech engine driver implementation from the pyttsx.drivers module. After construction, an application uses the engine object to register and unregister event callbacks; produce and stop speech; get and set speech engine properties; and start and stop event loops.

The Engine factory

pyttsx.init([driverName : string, debug : bool]) → pyttsx.Engine

Gets a reference to an engine instance that will use the given driver. If the requested driver is already in use by another engine instance, that engine is returned. Otherwise, a new engine is created.

Parameters:
  • driverName

    Name of the pyttsx.drivers module to load and use. Defaults to the best available driver for the platform, currently:

    • sapi5 - SAPI5 on Windows
    • nsss - NSSpeechSynthesizer on Mac OS X
    • espeak - eSpeak on every other platform
  • debug – Enable debug output or not.
Raises:
  • ImportError – When the requested driver is not found
  • RuntimeError – When the driver fails to initialize

The Engine interface

class pyttsx.engine.Engine

Provides application access to text-to-speech synthesis.

connect(topic : string, cb : callable) → dict

Registers a callback for notifications on the given topic.

Parameters:
  • topic – Name of the event to subscribe to.
  • cb – Function to invoke when the event fires.
Returns:

A token that the caller can use to unsubscribe the callback later.

The following are the valid topics and their callback signatures.

started-utterance

Fired when the engine begins speaking an utterance. The associated callback must have the folowing signature.

onStartUtterance(name : string) → None
Parameters:name – Name associated with the utterance.
started-word

Fired when the engine begins speaking a word. The associated callback must have the folowing signature.

onStartWord(name : string, location : integer, length : integer)
Parameters:name – Name associated with the utterance.
finished-utterance

Fired when the engine finishes speaking an utterance. The associated callback must have the folowing signature.

onFinishUtterance(name : string, completed : bool) → None
Parameters:
  • name – Name associated with the utterance.
  • completed – True if the utterance was output in its entirety or not.
error

Fired when the engine encounters an error. The associated callback must have the folowing signature.

onError(name : string, exception : Exception) → None
Parameters:
  • name – Name associated with the utterance that caused the error.
  • exception – Exception that was raised.
disconnect(token : dict)

Unregisters a notification callback.

Parameters:token – Token returned by connect() associated with the callback to be disconnected.
endLoop() → None

Ends a running event loop. If startLoop() was called with useDriverLoop set to True, this method stops processing of engine commands and immediately exits the event loop. If it was called with False, this method stops processing of engine commands, but it is up to the caller to end the external event loop it started.

Raises RuntimeError:
 When the loop is not running
getProperty(name : string) → object

Gets the current value of an engine property.

Parameters:name – Name of the property to query.
Returns:Value of the property at the time of this invocation.

The following property names are valid for all drivers.

rate

Integer speech rate in words per minute. Defaults to 200 word per minute.

voice

String identifier of the active voice.

voices

List of pyttsx.voice.Voice descriptor objects.

volume

Floating point volume in the range of 0.0 to 1.0 inclusive. Defaults to 1.0.

isBusy() → bool

Gets if the engine is currently busy speaking an utterance or not.

Returns:True if speaking, false if not.
runAndWait() → None

Blocks while processing all currently queued commands. Invokes callbacks for engine notifications appropriately. Returns when all commands queued before this call are emptied from the queue.

say(text : unicode, name : string) → None

Queues a command to speak an utterance. The speech is output according to the properties set before this command in the queue.

Parameters:
  • text – Text to speak.
  • name – Name to associate with the utterance. Included in notifications about this utterance.
setProperty(name, value) → None

Queues a command to set an engine property. The new property value affects all utterances queued after this command.

Parameters:
  • name – Name of the property to change.
  • value – Value to set.

The following property names are valid for all drivers.

rate

Integer speech rate in words per minute.

voice

String identifier of the active voice.

volume

Floating point volume in the range of 0.0 to 1.0 inclusive.

startLoop([useDriverLoop : bool]) → None

Starts running an event loop during which queued commands are processed and notifications are fired.

Parameters:useDriverLoop – True to use the loop provided by the selected driver. False to indicate the caller will enter its own loop after invoking this method. The caller’s loop must pump events for the driver in use so that pyttsx notifications are delivered properly (e.g., SAPI5 requires a COM message pump). Defaults to True.
stop() → None

Stops the current utterance and clears the command queue.

The Voice metadata

class pyttsx.voice.Voice

Contains information about a speech synthesizer voice.

age

Integer age of the voice in years. Defaults to None if unknown.

gender

String gender of the voice: male, female, or neutral. Defaults to None if unknown.

id

String identifier of the voice. Used to set the active voice via pyttsx.engine.Engine.setPropertyValue(). This attribute is always defined.

languages

List of string languages supported by this voice. Defaults to an empty list of unknown.

name

Human readable name of the voice. Defaults to None if unknown.

Examples

Speaking text

import pyttsx
engine = pyttsx.init()
engine.say('Sally sells seashells by the seashore.')
engine.say('The quick brown fox jumped over the lazy dog.')
engine.runAndWait()

Listening for events

import pyttsx
def onStart(name):
   print 'starting', name
def onWord(name, location, length):
   print 'word', name, location, length
def onEnd(name, completed):
   print 'finishing', name, completed
engine = pyttsx.init()
engine.connect('started-utterance', onStart)
engine.connect('started-word', onWord)
engine.connect('finished-utterance', onEnd)
engine.say('The quick brown fox jumped over the lazy dog.')
engine.runAndWait()

Interrupting an utterance

import pyttsx
def onWord(name, location, length):
   print 'word', name, location, length
   if location > 10:
      engine.stop()
engine = pyttsx.init()
engine.connect('started-word', onWord)
engine.say('The quick brown fox jumped over the lazy dog.')
engine.runAndWait()

Changing voices

engine = pyttsx.init()
voices = engine.getProperty('voices')
for voice in voices:
   engine.setProperty('voice', voice.id)
   engine.say('The quick brown fox jumped over the lazy dog.')
engine.runAndWait()

Changing speech rate

engine = pyttsx.init()
rate = engine.getProperty('rate')
engine.setProperty('rate', rate+50)
engine.say('The quick brown fox jumped over the lazy dog.')
engine.runAndWait()

Changing volume

engine = pyttsx.init()
volume = engine.getProperty('volume')
engine.setProperty('volume', volume-0.25)
engine.say('The quick brown fox jumped over the lazy dog.')
engine.runAndWait()

Running a driver event loop

engine = pyttsx.init()
def onStart(name):
   print 'starting', name
def onWord(name, location, length):
   print 'word', name, location, length
def onEnd(name, completed):
   print 'finishing', name, completed
   if name == 'fox':
      engine.say('What a lazy dog!', 'dog')
   elif name == 'dog':
      engine.endLoop()
engine = pyttsx.init()
engine.connect('started-utterance', onStart)
engine.connect('started-word', onWord)
engine.connect('finished-utterance', onEnd)
engine.say('The quick brown fox jumped over the lazy dog.', 'fox')
engine.startLoop()

Using an external event loop

engine = pyttsx.init()
engine.say('The quick brown fox jumped over the lazy dog.', 'fox')
engine.startLoop(False)
# engine.iterate() must be called inside externalLoop()
externalLoop()
engine.endLoop()