(This feature requires PowerPoint for Microsoft 365 for Mac version 16.22.127.0 or higher.) Set up captions and subtitles (By default, it's off.) Then, in Slide Show and Presenter View, a live transcription of your words will appear on-screen.
To have subtitles always start up when a Slide Show presentation starts, from the ribbon you can navigate to Slide Show > Always Use Subtitles to turn this feature on for all presentations. You can also toggle subtitles from the right-click menu, or with the shortcut key J. If you're in the middle of giving a presentation and want to turn the feature on or off, click the Toggle Subtitles button from Slide Show View or Presenter View, on the toolbar below the main slide: Turn the feature on or off while presenting You can change the background to improve contrast and make text easier to read. You can change the color, size, transparency, and font style of the subtitles. More appearance settings are available by clicking Subtitle Settings > More Settings (Windows). They can appear over the top or bottom margin of the slide (overlaid), or they can appear above the top or below the bottom of the slide (docked). In the Subtitle Settings menu, set the desired position of the captions or subtitles. By default, this will be the same language as your Spoken Language, but it can be a different language, meaning that translation will occur. This is the language of the text that will be shown to your audience. Use Subtitle Language to see which languages PowerPoint can display on-screen as captions or subtitles, and select the one you want. (By default, this will be set to the language corresponding to your Office editing language.) This is the language that you will be speaking while presenting. Use Spoken Language to see the voice languages that PowerPoint can recognize, and select the one you want. Or, you can adjust the settings without leaving your presentation through the context menu, Slide Show or Presenter View menus > Subtitle Settings > More Settings.
On the Slide Show ribbon tab, select Subtitle Settings. You can select the specific microphone you want to be used (if there is more than one microphone connected to your device), the position where the subtitles appear on the screen (bottom or top, and overlaid or separate from slide), and other display options. You can choose which language you want to speak while presenting, and which language the caption/subtitle text should be shown in (i.e. The feature isn't supported if you're using an earlier version of Windows.) Set up captions and subtitles ( Requires Windows 10, and PowerPoint for Microsoft 365 version 1.20178 or higher on Current Channel.