I think it is probably going to work fine without the multiple file names once you are using changeLanguageModelToFile: in line with its design. Keep in mind that changeLanguageModelToFile: gets used on already-started listening loop, so don’t stop and start the listening loop in order to change models, just send the change message as a result of whatever the change event is and it will change, just like it works in the sample app. Something that might be a bit of a red herring for you with the sample app is that it has a startListening method, but this only part of the design of the sample app so that I can demonstrate how to recover from a route change or phone call interruption. The way to start listening is by using – (void) startListeningWithLanguageModelAtPath:dictionaryAtPath:acousticModelAtPath:languageModelIsJSGF: and the tutorial is probably a better way to get an understanding of how those calls should be invoked, with the sample app only used for confirming how changing models on the fly works.