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.
If you want to use a different language, select it from the list provided. Verify the on-screen caption/sub-title language that PowerPoint can recognize by clicking Subtitle Language. The language chosen will display to the audience. By default, this will be set to the language corresponding to your Office language.
By default, this will be set to the language corresponding to your Office language. Verify the voice language that PowerPoint can recognize by clicking Spoken Language. If desired or needed, customize the settings: