Explanation:
Box 1: AudioConfig
If you want to specify the audio input device, then you need to create an AudioConfig class instance and provide the audioConfig parameter when initializing TranslationRecognizer.
If you want to provide an audio file instead of using a microphone, you still need to provide an audioConfig parameter.
Box 2: TranslationRecognizer
* TranslationRecognizer
Initialize a translation recognizer
After you created a SpeechTranslationConfig instance, the next step is to initialize TranslationRecognizer. When you initialize TranslationRecognizer, you need to pass it your speechTranslationConfig instance. The configuration object provides the credentials that the Speech service requires to validate your request.
Reference:
https://learn.microsoft.com/en-us/azure/ai-services/speech-service/how-to-translate-speech