Basics of Java Speech Grammar Format ( JSGF )

Hello Everyone,

This post is my response to those 4 help requests that i received in last few days. This one is going to be very basic and essentials of Java Speech Grammar Format ( JSGF ).

Every single file defines a single grammar only. Each grammar contains two parts:

The grammar header and the grammar body.

Grammar header format : #JSGF version char-encoding locale;

“#JSGF” is required and “version char-encoding locale;” is optional.

Grammar header example : #JSGF V1.0; & #JSGF V1.0 ISO8859-5 en;

After declaring Grammar Header, We need to specify the Grammar name.

Grammar name format : grammar grammarName;

This is a mandatory line. Else javax.speech.recognition.GrammarException will be thrown. Not only on Grammar Name, you will get GrammarExpection If you made any kind of mistake in grammar file.

Grammar Name Example : grammar helloWorld;

Once you are done with above part, you next step will be defining Grammar body.

The grammar body defines rules. you can define a rule only once. If you declare same rule twice then it will overwritten.

Rule Definition Format : public <ruleName> = ruleExpansion;

“public” is optional and remaining part is mandatory.

The rule expansion defines how the rule may be spoken. It is a logical combination of tokens (text that may be spoken) and references to other rules.

Rule Example : public <greet> = Hello;

The rule <greet> refers to a single token Hello. So to say rule <greet>, User must say word “Hello”.

A simple rule expansion can refer to one or more tokens or rules.

public <greet> = Hello;

public <completeGreet> = <greet> World;

Now, rule <completeGreet> refers to rule <greet> and token World. To say rule <completeGreet>, User must say “Hello World”.

Lets complete a simple “Hello World” grammar file.

#JSGF V1.0;

grammar simpleExample;

public <greet> = Hello;

public <completeGreet> = <greet> World;

This grammar file will allow you SR application to recognize 2 sentences. “Hello” and “Hello World”.

Now lets play a little bit with rule expansions.

Alternatives : “|”

public <greet> = Hello | Hey | Hi;

To say rule <greet>, User must say “Hello” or “Hey” or “Hi” But ONLY one of these three words.

Parentheses : “( )”

public <greet> = Hello ( World | User | Friend );

public <command> = ( Open | Close ) ( Door | Window );

To say rule <greet>, User must say “Hello World” or “Hello User” or “Hello Friend”.

And, to say rule <command>, User must say “Open Door” or “Open Window” or “Close Door” or “Close Window”.

Optional Grouping : “[ ]”

public <greet> = [ Hello ] World;

To say rule <greet>, User must say “Hello World” or “World”. As “Hello” is defined inside the Optional Grouping. So user may say it or not but “World” is mandatory.

Kleene Star : “*”

public <greet> = ( Hello | Hey | Hi )* World;

Any group or expansion followed by asterisk symbol indicates that it may be spoken zero or more times. For example “Hey Hello World” or “World” or “Hello Hello Hello World”.

Plus Operator : “+”

public <greet> = ( Hello | Hey | Hi )+ World;

A Plus Operator works same as “Kleene Star”, The only thing that makes difference is any group or expansion followed by plus symbol indicates that it may be spoken one ( NOT ZERO ) or more times.

You can also add comments in grammar file.

// One line comment

/* Multiple lines comment*/


* Documentation comment

* @author Puneet Kalra


Hope this tutorial clears all your doubts on JSGF.

More updates to come soon!


Expanding Dictionary Of Acoustic Model

Hello Everyone,

Today I’m going to tell you how to expand dictionary of acoustic model for Sphinx4. In simple words, This tutorial will tell you how you can add more words in Sphinx’s words database (Dictionary) and let it recognize those words, which are not available in default acoustic models provided by CMU Sphinx. This tutorial is based on “HelloWorld” example provided by CMU Sphinx.

Important Files in this example :

1 )

2) hello.gram

3) helloworld.config.xml

Acoustic Model used in this example :


Lets say, We are creating a SR system for ABC National airlines. Everything will go fine and Sphinx will recognize most of the words except the name of cities and states of India.  Now, I will tell you, How to add name of cities and states in dictionary.


Step 1 : Create a txt file “words.txt”, Write all the names of cities and states in it and save.

Step 2 : Open this link :

Step 3 : On that page, go to “Sentence corpus file:” section, Browse to “words.txt” file and click “Compile Knowledge Base”.

Step 4 : On next page, Click on “Dictionary” link and save that .DIC file.


Step 1 : Extract WSJ_8gau_13dCep_16k_40mel_130Hz_6800Hz.jar file.

Step 2 : Go to edu\cmu\sphinx\model\acoustic\WSJ_8gau_13dCep_16k_40mel_130Hz_6800Hz\dict folder.

Step 3 : Open “cmudict.0.6d” file in that folder.

Step 4 : Copy data from .DIC file, you have downloaded in PART ONE, paste it in “cmudict.0.6d” file and save.

Step 5 : Zip the extracted hierarchy back as it was and Zip file named should be same as JAR file.

Now, remove “WSJ_8gau_13dCep_16k_40mel_130Hz_6800Hz.jar” file from Project’s CLASSPATH and add “” instead of it.

That’s it ! We are done.  Now Sphinx will also recognize all name of cities and states that we wrote in “words.txt” file.

Now, FAQ time. I will be posting FAQ and few important notes in comments. 🙂

If you have any quires, Please feel free to ask.


Speech Recognizer In Java (Tutorial)

Hello All,

This is my first video tutorial. This tutorial demonstrates how to make a speech recognizer in java using Sphinx.

Requirements to work according to the tutorial :

1 ) JDK 6 ( J2SE )

2 ) Eclipse SDK ( Im using Eclipse 3.4.0 )

3 ) Sphinx 4.0

4 ) JSAPI ( Included in Sphinx 4.0 )

Tutorial is divided into 3 parts.

Please feel free to post your comments and suggestions on tutorial and help me to improve the quality.


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