IBM TTS

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The Text to Speech service understands text and natural language to generate synthesized audio output complete with appropriate cadence and intonation. It is available in 13 voices across 7 languages. Select voices now offer Expressive Synthesis.

 

The IBM® Text to Speech service provides an Application Programming Interface (API) that uses IBM’s speech-synthesis capabilities to convert written text to natural-sounding speech. The service streams the results back to the with minimal delay. The service offers the following features:

  • HTTP and WebSocket interfaces: Supports speech synthesis via both HTTP REST and WebSocket interfaces. Both interfaces support the use of SSML, and the WebSocket interface also supports the SSML <mark> element to synchronize the audio and input text, for example, for use with robots. See Using the HTTP interface andUsing the WebSocket interface.
  • Audio formats: Produces Ogg format with the opus codec (the default), Waveform Audio File Format (WAV), Free Lossless Audio Codec (FLAC), Linear 16-bit Pulse-Code Modulation (PCM), or basic audio files. SeeSpecifying an audio format.
  • Voices: Synthesizes text to audio in a variety of languages, including English, French, German, Italian, Japanese, Spanish, and Brazilian Portuguese. The service offers at least one male or female voice, sometimes both, for each language and different dialects such as US and UK English and Castilian and North American Spanish. The audio uses appropriate cadence and intonation. See Specifying a voice.
  • SSML: Accepts plain text or text annotated with the Speech Synthesis Markup Language (SSML), an XML-based markup language that provides annotations of text for speech synthesis applications. See Specifying SSML input.
  • Expressive SSML: Augments SSML with an expressive element that lets you indicate a speaking style ofGoodNews, Apology, or Uncertainty. Currently available only for the US English Allison voice. See Specifying expressive SSML.
  • Customization: Provides a customization interface that lets you specify how it pronounces unusual words that occur in your input. See Understanding customization.