In addition to the Simple Grammar format shown in most of our code examples, Tropo supports GrXML grammars for speech recognition. Provide the URL to a GrXML file as your "choices" parameter in the ask function and Tropo will download and use that grammar.
By default, only simple, single-slot directed speech grammars are supported.
Be aware that Tropo does not support all features of the GrXML spec. Some capabilities need an advanced speech science degree to make work with high accuracy or are extremely resource intensive to our platform and so are disabled in Tropo. Multi-slot grammars are available as a premium Tropo feature. Developers must ask Tropo support to have an account enabled for multislot grammars. Once enabled, each speech recognition event in your application will be billed as an additional charge. If your account is not enabled for multislot grammars, then attempting to return multiple slots in your grammar will result in an application error.
GrXML special rules like GARBAGE, and Free Form SLM and SSM are not available in the standard platform, but options exist for customers with advanced speech requirements. If you need these advanced features beyond the standard Directed Dialog approach, please contact Tropo sales and we will work with you on options.
Writing GrXML grammars is usually a job for a professional, and people make their living doing nothing but writing these advanced grammars. We recommend that you start your speech recognition journey with Tropo's Simple Grammar approach. Once you are confident with that and want to explore further, then consult the GrXML spec or hire a speech professional for more complex tasks.