VoxForge is a free

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

 speech corpus

Speech corpus

A speech corpus is a database of speech audio files and text transcriptions.In Speech technology, speech corpora are used, among other things, to create acoustic models ....

 and acoustic model

Acoustic Model

An acoustic model is created by taking audio recordings of speech, and their text transcriptions, and using software to create statistical representations of the sounds that make up each word. It is used by a speech recognition engine to recognize speech....

 repository for open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 speech recognition

Speech recognition

Speech recognition converts spoken words to text. The term "voice recognition" is sometimes used to refer to recognition systems that must be trained to a particular speaker—as is the case for most desktop recognition software...

 engines.

VoxForge was set up to collect transcribed speech to create a free GPL

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

 speech corpus for use with open source speech recognition engines. The speech audio files will be 'compiled' into acoustic models for use with open source speech recognition engines such as Julius

Julius (software)

Julius is an open source speech recognition engine.Julius is a high-performance, two-pass large vocabulary continuous speech recognition decoder software for speech-related researchers and developers. Based on word 3-gram and context-dependent HMM, it can perform almost real-time decoding on most...

, ISIP, and Sphinx

CMU Sphinx

CMU Sphinx, also called Sphinx in short, is the general term to describe a group of speech recognition systems developed at Carnegie Mellon University...

 and HTK

HTK (software)

HTK is software toolkit for handling HMMs. It is mainly intended for speech recognition, but has been used in many other pattern recognition applications that employ HMMs.-External links:** using the TIMIT speech corpus...

 (note: HTK has distribution restrictions).

VoxForge has recently started to use LibriVox

LibriVox

LibriVox is an online digital library of free public domain audiobooks, read by volunteers and is probably, since 2007, the world's most prolific audiobook publisher...

as a source of audio data.