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Improving Open Source Speech Recognition
kmaclean writes, "VoxForge
collects free GPL Transcribed Speech Audio that can be used in the creation of Acoustic Models for use with Open Source Speech Recognition Engines. We are essentially
creating a user-submitted repository of the 'source' speech audio for
the creation of Acoustic Models to be used by Speech Recognition Engines. The Speech
Audio files will then be 'compiled' into Acoustic Models for use with
Open Source Speech Recognition engines such as Sphinx, HTK, CAVS and Julius." Read on for why we need free GPL speech audio.
Why free GPL Speech Audio?
Speech Recognition Engines require two types of files to recognize speech. The first is an Acoustic Model, which is created by taking a very large number of audio recordings of speech and their transcriptions (called Speech Corpus or Corpora) and 'compiling' them into statistical representations of the sounds that make up each word. The second is a Language Model or Grammar file. A Language Model is a very large file containing the probabilities of certain sequences of words. A Grammar is a much smaller file containing sets of predefined combinations of words.
Most Acoustic Models used by 'Open Source' Speech Recognition engines are 'closed source'. They do not give you access to the speech audio (the 'source') used to create the acoustic model, or if they do, there are licensing restrictions on the distribution of the 'source' (i.e. you can only use it for personal or research purposes). The reason for this is because there is no free Speech Corpora in a form that can readily be used to create Acoustic Models for Speech Recognition Engines. Open Source projects are required to purchase Speech Copora which has restrictive licensing — i.e. they are not permitted to distribute the 'source' speech audio, but they are permitted them to distributed the 'compiled' Acoustic Model.
Why GPL?
A GPL-style license will ensure that user contributions will always benefit the open source community, since it requires any distribution of derivative Acoustic Models to include access to the 'source' speech audio.
Why free GPL Speech Audio?
Speech Recognition Engines require two types of files to recognize speech. The first is an Acoustic Model, which is created by taking a very large number of audio recordings of speech and their transcriptions (called Speech Corpus or Corpora) and 'compiling' them into statistical representations of the sounds that make up each word. The second is a Language Model or Grammar file. A Language Model is a very large file containing the probabilities of certain sequences of words. A Grammar is a much smaller file containing sets of predefined combinations of words.
Most Acoustic Models used by 'Open Source' Speech Recognition engines are 'closed source'. They do not give you access to the speech audio (the 'source') used to create the acoustic model, or if they do, there are licensing restrictions on the distribution of the 'source' (i.e. you can only use it for personal or research purposes). The reason for this is because there is no free Speech Corpora in a form that can readily be used to create Acoustic Models for Speech Recognition Engines. Open Source projects are required to purchase Speech Copora which has restrictive licensing — i.e. they are not permitted to distribute the 'source' speech audio, but they are permitted them to distributed the 'compiled' Acoustic Model.
Why GPL?
A GPL-style license will ensure that user contributions will always benefit the open source community, since it requires any distribution of derivative Acoustic Models to include access to the 'source' speech audio.
I'll pitch in. I lost the use of my hands for three years due to a repetitive motion injury, and had to code by voice. That was 1997, nine years ago. I figured that within a couple years, the technology would be so great I would out-code my peers. Then the web bubble came, and Dragon Systems lost their focus on helping disabled people and focused instead on letting people dictate to Word. The creators of this great technology eventually sold out and moved on. Nine years later, the best product for coding is nine years old: the original Dragon Dictate. It doesn't even use the CPU for it's signal processing: it runs that on the sound card because in the early 90's the sound card had more power.
We've gotta do something to get this beast moving forward.
Beer is proof that God loves us, and wants us to be happy.
Back in roughly 1991 or 1992, I was working at Commodore/Amiga with AT&T DSP3210's (we were considering adding them to Amiga 3000's/4000's). They supported speech recognition, and due to that (somehow) I was asked to participate in a NIST program to collect speech samples over telephone. You made calls where you were randomly connected to another participant, and talked about a given topic. I imagine they were later transcribed; the purpose of this was to create a natural (connected) speech database for speech recognition researchers and vendors.
Since it was done by NIST, I imagine the database is available. Note that it will be limited by the telephone call quality (4KHz).