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Audio and Prompts Discussions

Designing grammars
User: colbec
Date: 3/10/2008 8:25 am
Views: 3732
Rating: 24
Has any work been done on manipulating grammars and prompt lists with databases? Seems like an ideal environment in which to test phonetic balance, adequate coverage of words in prompts, suggesting extra words to improve phonetic balance, etc.

--- (Edited on 3/10/2008 8:25 am [GMT-0500] by colbec) ---

Re: Designing grammars
User: nsh
Date: 3/10/2008 11:39 am
Views: 237
Rating: 20
Can you explain a little bit about this question, it's not quite clear what are you asking about.

--- (Edited on 3/10/2008 11:39 am [GMT-0500] by nsh) ---

Re: Designing grammars
User: colbec
Date: 3/10/2008 12:15 pm
Views: 229
Rating: 22

Apologies for the terseness, here is a bit more detail:

For example this morning I was playing with a grammar designed to query a database. I followed the rules as described in the Julius and HTK manuals to come up with a good selection of words (or so I thought!).

Clearly, it is important to choose the right words, there must be a good differentiation between words to help the engine distinguish clearly between them and in order to do this, as the tutorial shows, you select the right mix of phonemes.

Building the right fundamental grammar and the best prompts to go with it could be a bit tedious given the need to keep track of large numbers of words, and avoiding the temptation to select from the top end of an alphabetically sorted list.

So I built a small access database and read into it my own grammar and the list of words from the voxforge lexicon.

This means I can quickly: check that my chosen words are in the lexicon, update my table of words with the appropriate phonemes, print out a .voca file, check to see which phonemes my word list does not contain or where my current word mix is weak phonemetrically, isolate words from the lexicon that offer the needed phonemes, etc.

With a bit more work it could come up with suggested sentences however meaningless that still contain complementary prompts.

--- (Edited on 3/10/2008 12:15 pm [GMT-0500] by colbec) ---

Re: Designing grammars
User: nsh
Date: 3/10/2008 12:47 pm
Views: 268
Rating: 20

Well actually modern state of art in grammar design includes many more things. Current command and control is more a keyword spotting with low-probability phone loop for OOV words than a strict grammar selection. I wonder if phoneset selection is really efficient here, user can say anything actually, you only need to catch the right phrase

Google tech talk

has a little introduction into this.

About prompts generation from the grammar, HTK has tools for that:

 HSGen -l -n 200 wdnet dict 

will do everything you need. 

--- (Edited on 3/10/2008 12:47 pm [GMT-0500] by nsh) ---

Re: Designing grammars
User: colbec
Date: 3/10/2008 1:41 pm
Views: 1333
Rating: 19

Thanks for the thoughts. I don't have a 'net connection that can handle video stuff so cannot benefit from that.

I suppose it is still arguable that efficient grammar design and phoneset selection helps to catch the right phrase earlier than otherwise.

--- (Edited on 3/10/2008 1:41 pm [GMT-0500] by colbec) ---