That’s fine, but in order to troubleshoot it more we need to look at a setup where normal recognition is expected to work, while the simulator is a setup where normal recognition is not expected to work. Can you start with taking either the tutorial output or the sample app and just replacing the vocabulary with your own vocabulary, verifying that it works, and then one step at a time adding your customizations? That should point up any issue very quickly. Make sure not to set OEPocketsphinxController to return null hyps since the important part is only whether your app-oriented speech is not being heard, rather than the presence of null hyps in and of themselves, which is expected.