If you want to improve speech recognition speed or use the DroidScript 'Speech Recognition' or 'Voice Command' examples while you are offline in Android 7 then you will need to do a couple of things to make it work:-
1. Switch your default device language to English (US)
2. Go to the Settings/Google/Search/Voice options and select the 'Offline speech recognition' option and download English (US)
(Only US English seems to be supported by Google at the moment)
Now you can make your own voice controlled personal slave robot ;)