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Sphinx is a speaker-independent large vocabulary continuous speech recognizer. It is also a collection of free and open source tools and resources that allows researchers and developers to build speech recognition systems. The packages that the CMU Sphinx Group is releasing are a set of reasonably mature, world-class speech components that provide a basic level of technology to anyone interested in creating speech-using applications without the once-prohibitive initial investment cost in research and development; the same components are open to peer review by all researchers in the field, and are used for linguistic research as well. Sphinx-2 is a fast speech recognition system, the predecessor of PocketSphinx. It is not being actively developed at this time, but is still widely used in interactive applications. It uses Hidden Markov Models (HMM) with semi-continuous output probability density functions (PDF). Even though it is not as accurate as Sphinx-3 or Sphinx-4, it runs at real time, and therefore it is a good choice for live applications. You can find further documentation about Sphinx-2 in the release documentation, or at the online documentation.

Documentation and


Download version 0.6 (beta)
released on 17 February 2009


Related Projects


LicenseVerified byVerified onNotes
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Leaders and contributors

Evandro Gouvêa Maintainer
Mosur Ravishankar Maintainer

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Software prerequisites

This entry (in part or in whole) was last reviewed on 17 February 2009.


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