在MacOS上以编程方式切换口述

import Speech

SFSpeechRecognizer.requestAuthorization { (status) in
    if status == .authorized {
        // 用户已授权
    } else {
        // 用户未授权
    }
}

let recognizer = SFSpeechRecognizer()

let audioSession = AVAudioSession.sharedInstance()
try? audioSession.setCategory(.record, mode: .measurement, options: .duckOthers)
try? audioSession.setActive(true, options: .notifyOthersOnDeactivation)

let recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
let inputNode = audioEngine.inputNode

recognitionRequest.shouldReportPartialResults = true

let recognitionTask = recognizer?.recognitionTask(with: recognitionRequest, resultHandler: { (result, error) in
    if let result = result {
        let transcription = result.bestTranscription.formattedString
        // 处理识别结果
    } else if let error = error {
        // 处理错误
    }
})

inputNode.installTap(onBus: 0, bufferSize: 1024, format: inputNode.outputFormat(forBus: 0)) { (buffer, time) in
    recognitionRequest.append(buffer)
}

audioEngine.prepare()
try? audioEngine.start()

recognitionTask?.finish()
audioEngine.stop()
recognitionRequest.endAudio()