PowerPoint for Office 365 offers the option to create subtitles and closed captions for individuals who are hearing impaired. This option will benefit other learners as well, including those without a hearing disability.

When subtitles are enabled in the PowerPoint slide deck, as the presenter speaks, subtitles/captions will be displayed in real-time. The accuracy of the subtitles/captions will vary depending on the quality of the microphone used, clarity of the speaker, environmental noise, etc.

The following two resources will demonstrate how to enable subtitles/captions in PowerPoint for Office 365.

Use Live Subtitles in your Presentation (YouTube Video) 

Present with Real-Time Automatic Captions or Subtitles in PowerPoint