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Speech Library for the D Programming Language
D Other

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speech4d - Speech Library for the D Programming Language

speech4d is a library aiming at providing comprehensive TTS (Text To Speech) and voice recognition capabilities for the D programming language, in the form of a cross-platform high level interface, as well as low level engine bindings.

Text To Speech

The high level interface currently only has a Windows Speech API backend.

speech4d also includes bindings for the Windows Speech API and the cross-platform eSpeak API.

Voice Recognition

No work has been done on voice recognition yet. The current focus is on the TTS libraries.

Directory Structure

  • speech - the speech4d top package.
  • visuald - VisualD project files.
  • test - test sources and binaries (when built).
  • lib - speech4d library files (when built).

Building with VisualD

The Microsoft Speech API (SAPI) is a system library included with Windows. An import library for SAPI in the OMF format required by DMD32 can be found here as a convenience. The project files will look for the import library at lib/sapi.lib.

eSpeak on Windows comes with either its own cross-platform API or as a backend voice supplier to the Microsoft SAPI. On Windows, the cross-platform API only supports synchronous retrieval of audio data, no playback or asynchronous retrieval, hence the SAPI backend is preferable on this platform.

The eSpeak SAPI provider can be found on the eSpeak downloads page.

A Windows DLL and import library for the cross-platform eSpeak library can nonetheless be found here.


Documentation can be found on the gh-pages branch, or read online here.

Documentation for the Windows Speech API and the eSpeak API can be found at their respective websites.


speech4d is licensed under the terms of the MIT license (see the LICENSE.txt file for details).

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