import UIKitimport Speechclass ViewController: UIViewController, SFSpeechRecognizerDelegate ,AVSpeechSynthesizerDelegate { @IBOutlet weak var textView: UITextView! private let speechRecognizer = SFSpeechRecognizer(locale: Locale.init(identifier: "en-US"))! private var recognitionRequest: SFSpeechAudioBufferRecognitionRequest? private var recognitionTask: SFSpeechRecognitionTask? private let audioEngine = AVAudioEngine() private var audio : AVAudioInputNode? = nil var audioSession : AVAudioSession? = nil override func viewDidLoad() { super.viewDidLoad() self.getSpeech(asSpeach: "how are you ?") speechRecognizer.delegate = self SFSpeechRecognizer.requestAuthorization { (authStatus) in var isButtonEnabled = false switch authStatus { case .authorized: isButtonEnabled = true case .denied: isButtonEnabled = false print("User denied access to speech recognition") case .restricted: isButtonEnabled = false print("Speech recognition restricted on this device") case .notDetermined: isButtonEnabled = false print("Speech recognition not yet authorized") } } } func endAudio() { if audioEngine.isRunning { AudioOutputUnitStop((audioEngine.inputNode?.audioUnit)!) AudioUnitUninitialize((audioEngine.inputNode?.audioUnit)!) audioEngine.stop() } } func startRecording() { if recognitionTask != nil { recognitionTask?.cancel() recognitionTask = nil } AudioOutputUnitStop((audioEngine.inputNode?.audioUnit)!) AudioUnitUninitialize((audioEngine.inputNode?.audioUnit)!) audioSession = AVAudioSession.sharedInstance() do { try audioSession?.setCategory(AVAudioSessionCategoryPlayAndRecord) try audioSession?.setMode(AVAudioSessionModeMeasurement) try audioSession?.setActive(true, with: .notifyOthersOnDeactivation) } catch { print("audioSession properties weren't set because of an error.") } recognitionRequest = SFSpeechAudioBufferRecognitionRequest() guard let inputNode = audioEngine.inputNode else { print("Audio engine has no input node") } audio=inputNode audio?.removeTap(onBus: 2) guard let recognitionRequest = recognitionRequest else { fatalError("Unable to create an SFSpeechAudioBufferRecognitionRequest object") } recognitionRequest.shouldReportPartialResults = true recognitionTask = speechRecognizer.recognitionTask(with: recognitionRequest, resultHandler: { (result, error) in var isFinal = false if result != nil { self.textView.text = result?.bestTranscription.formattedString isFinal = (result?.isFinal)! if self.textView.text == "Fine" || self.textView.text == "Find" { self.audioEngine.stop() self.textView.text = "" DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) { self.getSpeech(asSpeach: "how are you ?") } } } if error != nil || isFinal { self.audioEngine.stop() inputNode.removeTap(onBus: 2) self.recognitionRequest = nil self.recognitionTask = nil } }) let recordingFormat = inputNode.outputFormat(forBus: 2) inputNode.installTap(onBus: 2, bufferSize: 1024, format: recordingFormat) { (buffer, when) in self.recognitionRequest?.append(buffer) } audioEngine.prepare() do { try audioEngine.start() } catch { print("audioEngine couldn't start because of an error.") } textView.text = "Say something, I'm listening!" } func speechRecognizer(_ speechRecognizer: SFSpeechRecognizer, availabilityDidChange available: Bool) { if available { //something } else { //else thing } } func getSpeech(asSpeach:String) { audioSession = AVAudioSession.sharedInstance() do { try audioSession?.overrideOutputAudioPort(.speaker) } catch { print(error.localizedDescription) } let synthesizer = AVSpeechSynthesizer() let utterance = AVSpeechUtterance(string: asSpeach) utterance.rate = AVSpeechUtteranceDefaultSpeechRate synthesizer.delegate=self synthesizer.speak(utterance) } public func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) { audioEngine.stop() do { try audioSession?.setActive(false) } catch { print("error.localizedDescription") print(error.localizedDescription) } print("speech synthesizer ended") if(audioEngine.isRunning) { endAudio() } DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) { self.startRecording() } }}As requirement first dictet one string and if the string is a keyword (as per business rule) dictet again but getting crash think the crash is for mismatching the audioformat for dictet and speech .The error message isERROR: [0x1b2a4cb40] >avae> AVAudioIONodeImpl.mm:884: SetOutputFormat: required condition is false: format.sampleRate == hwFormat.sampleRateTerminating app due to uncaught exception 'com.apple.coreaudio.avfaudio', reason: 'required condition is false: format.sampleRate == hwFormat.sampleRate'Think the problem is with AVAudioSession please suggest i am trying many times but dont have a luck till now