Quinn,
Are there any updates, speech recognition service still doesn't work on real device while it does work in simulator following https://stackoverflow.com/questions/59786548/sfspeechrecognizer-fails-with-error-kafassistanterrordomain-code-1107.
Update:
let recognizer = SFSpeechRecognizer(locale: Locale(identifier: "en-US"))
let recognizer = SFSpeechRecognizer(locale: Locale(identifier: "en-GB"))
worked for me. It shouldn't make a big difference though.