Supports the creation of Speech Synthesis Markup Language (SSML) based custom engines for rendering text to speech (TTS).

The members of the System.Speech.Synthesis.TtsEngine namespace make available Windows Desktop Speech Technology support for Speech Synthesis Markup Language (SSML) based markup language and the construction of synthetic speech engines.

The SSML markup language is the industry standard to provide a rich, XML-based language for assisting the synthetic speech engines. It is endorsed by Microsoft and our competitors. For more information on SSML, see Speech Synthesis Markup Language Specification.

Creating of a new of synthetic speech engine using System.Speech.Synthesis.TtsEngine requires the implementation and registration of an object derived from the abstract base class TtsEngineSsml.

System.Speech.Synthesis.TtsEngine based synthetic speech engines are accessed through Windows Desktop Speech Technology infrastructure, using the tools in the System.Speech.Synthesis namespace, in particular SpeechSynthesizer object, and are never directly used by applications.

The Windows Desktop Speech Technology infrastructures ensures that all parameters passed to a synthetic speech engine are validated and thread synchronized.

A of synthetic speech engine implemented using System.Speech.Synthesis.TtsEngine technology can:

• Receive input, (see Speak,.TextFragment, FragmentState, and SkipInfo )

• Queue events, and specify actions TtsEngineAction, ITtsEngineSite, EventParameterType,

• Control the control the pitch, speaking rate and volume of the speech output (see ContourPoint, ContourPointChangeType, EmphasisBreak, EmphasisWord, Prosody, ProsodyNumber, ProsodyPitch, ProsodyRange, ProsodyRate, ProsodyUnit, andT:System.Speech.Synthesis.TtsEngine.ProsodyVolume)

• Determine usage and output target of speech synthesis (see SayAs, SpeakOutputFormat)