JSGF Grammar

The Java Speech Grammar Format (JSGF) is a textual representation of grammars used to create speech recognition applications. In speech enabled IVR applications, grammars are used by speech engines to match a caller's utterance to a specific grammar thus accepting speech as input. JSGF adopts the style and conventions of the Java programming language in addition to use of traditional grammar notations.

The JSGF grammar syntax is the default syntax for the Plum Voice Platform. JSGF can be used to specify speech and DTMF grammars. Refer to the JSGF Specification for further detail.

Since JSGF is not a part of the VoiceXML 2.0 specification, the integration of JSGF into the Plum Voice Platform has been based upon the VoiceXML 1.0 specification. JSGF is considered the default grammar type. To explicitly specify a JSGF grammar, set the "type" attribute of the grammar tag to "application/x-jsgf".

When specifying JSGF grammars inline, the grammar can be specified as a single alternative-set, as the headerless body of grammar (hence a series of rule definitions), or as a full grammar. Because both the headerless grammar body and the full grammars include "<" and ">" symbols, they need to be enclosed within CDATA delimiters ("") so that the VoiceXML interpreter does not get confused. When referencing external JSGF grammars via the "src" grammar attribute, the referenced grammar must be a full grammar. When multiple rules are present in a grammar, all of the grammar's public rules are active. If there are no public rules, then the first rule in the grammar encountered is considered the active rule.

Related links

• JSGF Specification - W3C
• Speech Recognition - Plum IVR Glossary
• DTMF Grammars - Plum IVR Glossary