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Speech Recognition Grammar Specification(SRGS) is a W3C Recommendation for specifying

speech recognition grammars

Grammars define the words andphrases a speechrecogniser may recognize

Grammars constrain speech recognition input toimprove recognition performance and accuracy

Introduction

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Two equivalent forms of SRGS:

XML Form

ABNF Form

SRGS is often used in conjunction with othertechnologies, for example:

VoiceXML

SALT

MRCP

Introduction

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Tutorial contents:

XML Form of SRGS

ABNF Form of SRGS

Using SRGS with VoiceXML

Goal: Enough knowledge to write functionalgrammars in both forms

Introduction

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yes please

XMLForm: Basic Structure

One or more rules

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XMLForm: Basic Structure

Root rule

yes please

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XMLForm: Basic Structure

Type of grammar; DTMF

grammars possible also

yes please

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XMLForm: Basic Structure

Language

yes please

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XMLForm: Sequences and Alternatives

Sequence

yes please

no thanks

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XMLForm: Sequences and Alternatives

yes please

no thanks

Alternatives

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XMLForm: Rule References

Rule Reference

one

two

three four

five

six

seven

eight nine

zero

ten

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Exercise 1: Write a grammar for digits

0 to 19

XMLForm: Exercise

one

two

three four

five

six

seven

eight nine

zero

ten

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ten

eleven

twelve thirteen

fourteen

fifteen

sixteen

seventeen

eighteen

nineteen

zero

Exercise 1: Answer

XMLForm: Exercise

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XMLForm: Repeats

very

good

very

good

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XMLForm: Garbage

Joe Bloggs

Examples:

Joe Bloggs

Joe R Bloggs

Joe Richard Bloggs

Joe Richie Bloggs

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XMLForm: Semantic Interpretation

coke coke

cola coke

coca cola coke

black fizzy stuff coke

Defines contents of

elements

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Exercise 2: Write a grammar for digits

0 to 50

(Hint: reuse rules #single_digits and #teens)

XMLForm: Exercise

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zero

twenty

twenty

thirty

thirty

fourty

fourty

fifty

Exercise 2: Answer

XMLForm: Exercise

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ABNF Form

Equivalent to XML Form (semantically

mappable)

More compact notation

Does not enjoy same benefits as XML

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ABNF Form: Basic Structure

One or more rules

#ABNF 1.0;

language en-US;mode=voice;

root $main;

$main=yes please;

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ABNF Form: Basic Structure

#ABNF 1.0;

language en-US;mode=voice;

root $main;

$main=yes please;

Root rule

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ABNF Form: Basic Structure

#ABNF 1.0;

language en-US;mode=voice;

root $main;

$main=yes please; Type of grammar

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ABNF Form: Basic Structure

Language

#ABNF 1.0;

language en-US;mode=voice;

root $main;

$main=yes please;

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ABNF Form: Sequences and Alternatives

Sequence

#ABNF 1.0;

language en-US;mode=voice;

root $main;

$main=yes please | no thanks;

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ABNF Form: Sequences and Alternatives

Alternatives

(note precedence!)

#ABNF 1.0;

language en-US;mode=voice;

root $main;

$main=yes please | no thanks;

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ABNF Form: Rule References

Rule Reference

#ABNF 1.0;

language en-US;

mode=voice;

root $pizza;

$pizza=I would like a $size pizza;

$size=small | medium | large;

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ABNF Form: Repeats

Repeat

#ABNF 1.0;

language en-US;

mode=voice;

root $thanks;

$thanks=thank you very much;

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ABNF Form: Garbage

#ABNF 1.0;

language en-US;

mode=voice;

root $name;

$name=Joe $GARBAGE Bloggs;

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ABNF Form: Semantic Interpretation

#ABNF 1.0;

language en-US;

mode=voice;

root $drink;

$drink=coke {coke} | cola {coke} | coca cola {coke};

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ABNF Form: Exercise

Exercise 3:

Write a grammar to accept the following input:

I would like to fly from ___ to ___ (please/thanks)

where the following cities are allowed:

paris, new york, dublin

and please or thanks is an optional extra

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ABNF Form: Exercise

#ABNF 1.0;

language en-US;mode=voice;

root $fly;

$fly=I would like to fly from $city to $city $manners;

$city=paris | new york | dublin;$manners=please | thanks;

Exercise 3: Answer

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ABNF Form: Exercise

#ABNF 1.0;

language en-US;

mode=voice;

root $fly;

$fly=I would like to fly from $city to $city [$manners];

$city=paris | new york | dublin;$manners=please | thanks;

Exercise 3: Answer

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SRGS with VoiceXML

VoiceXML allows grammars to be inline(embedded) orreferenced

The XML Form is required by VoiceXML;ABNF Form should be supported

Referencing grammars encouragesreusability

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SRGS with VoiceXML: Inline

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SRGS with VoiceXML: Referenced

Explicit rule reference

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SRGS with VoiceXML: Referenced

Preferred type

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Covered the major principles of the XML

Form and ABNF Form of SRGS

For more information consult:

http://www.w3.org/TR/speech-grammar/

http://www.w3.org/TR/semantic-interpretation/

http://www.w3.org/TR/voicexml20/

Summary