System.Speech.Synthesis Namespace

Contains classes for initializing and configuring a speech synthesis engine, for creating prompts, for generating speech, for responding to events, and for modifying voice characteristics.



Returns data from the BookmarkReached event.


Represents a prompt created from a file.


Contains information about a speech synthesis voice installed in Windows.


Returns data from the PhonemeReached event.


Represents information about what can be rendered, either text or an audio file, by the SpeechSynthesizer.


Creates an empty Prompt object and provides methods for adding content, selecting voices, controlling voice attributes, and controlling the pronunciation of spoken words.


Represents the base class for EventArgs classes in the System.Speech.Synthesis namespace.


Defines a style for speaking prompts that consists of settings for emphasis, rate, and volume.


Returns notification from the SpeakCompleted event.


Returns data from the SpeakProgress event.


Returns notification from the SpeakStarted event.


Provides access to the functionality of an installed speech synthesis engine.


Returns data from the StateChanged event.


Returns data from the VisemeReached event.


Returns data from the VoiceChange event.


Represents an installed speech synthesis engine.



Enumerates values for intervals of prosodic separation (breaks) between word boundaries.


Enumerates values for levels of emphasis in prompts.


Enumerates values for the speaking rate of prompts.


Enumerates values for volume levels (loudness) in prompts.


Enumerates the content types for the speaking of elements such as times, dates, and currency.


Enumerates the types of media files.


Enumerates the types of text formats that may be used to construct a Prompt object.


Enumerates levels of synthesizer emphasis.


Enumerates values for the state of the SpeechSynthesizer.


Defines the values for the age of a synthesized voice.


Defines the values for the gender of a synthesized voice.


Initialize and Configure

The SpeechSynthesizer class provides access to the functionality of a speech synthesis engine that is installed on the host computer. Installed speech synthesis engines are represented by a voice, for example Microsoft Anna. A SpeechSynthesizer instance initializes to the default voice. To configure a SpeechSynthesizer instance to use one of the other installed voices, call the SelectVoice or SelectVoiceByHints methods. To get information about which voices are installed, use the GetInstalledVoices method.

You can route the output of the SpeechSynthesizer to a stream, a file, the default audio device, or to a null device by using one of the methods in the SpeechSynthesizer class whose name begins with "SetOutputTo".

Create Prompts

Use one the methods of the PromptBuilder class whose name begins with "Append" to build content for prompts from text, Speech Synthesis Markup Language (SSML), files containing text or SSML markup, or prerecorded audio files.

See Constructing a Complex Prompt in the System Speech Programming Guide for .NET Framework for more information and examples.

Generate Speech

To generate speech from a string or from a Prompt or PromptBuilder object, use the Speak or the SpeakAsync methods. To generate speech from SSML markup, use the SpeakSsml or the SpeakSsmlAsync methods. See Speech Synthesis Markup Language Reference for a guide to SSML markup.

You can guide the pronunciation of words by using the AppendTextWithHint or AppendTextWithPronunciation methods, and by adding or removing lexicons for a SpeechSynthesizer instance using the AddLexicon and RemoveLexicon methods.

Respond to Events

The SpeechSynthesizer class includes events that inform a speech application that the SpeechSynthesizer encountered a specific feature in a prompt, as reported by the SpeakProgressEventArgs, BookmarkReachedEventArgs, PhonemeReachedEventArgs, and VisemeReachedEventArgs classes.

To get information about the beginning and end of the speaking of a prompt by the SpeechSynthesizer, use the SpeakStartedEventArgs and SpeakCompletedEventArgs classes.

See Using Speech Synthesis Events in the System Speech Programming Guide for .NET Framework for more information and examples.

Modify Voice Characteristics

The PromptStyle class and StartStyle and AppendText methods let you modify characteristics of a SpeechSynthesizer voice using Emphasis, Rate, and Volume parameters. To modify characteristics of a voice such as culture, age, and gender, use one of the StartVoice methods of the PromptBuilder class or the SelectVoiceByHints methods of the SpeechSynthesizer class.

See Controlling Voice Attributes in the System Speech Programming Guide for .NET Framework for more information.

See also