OK, well, let’s just pick a single Acoustic Model for this troubleshooting case so that we don’t have a lot of variables – you can tell me which one we’re using. I recommend the German one.
–> generateGrammar sais: “This will recognize exact phrases instead of probabilistically recognizing word combinations in any sequence.”
–> Rejecto’s doc sais: “Rejecto makes sure that your speech app does not attempt to recognize words which are not part of your vocabulary. This lets your app stick to listening for just the words it knows, and that makes your users happy.”
Yes, the intention of this documentation is to clarify that a grammar can listen for a multi-word phrase in exclusive terms (i.e. it won’t attempt to evaluate statistical nearness to your phrase but just try to hear it when complete, not hear it when not complete) and Rejecto will reject unknown words from a model made up of words. So if the goal is a sentence, a grammar is probably the right choice. If you were looking for one of several words by themselves, or phrases where you didn’t mind possible partial recognition of the phrase contents, Rejecto would be better.