Present with real-time, automatic captions or subtitles in PowerPoint

PowerPoint for Office 365 can transcribe your words as you present and display them on-screen as captions in the same language you are speaking, or as subtitles translated to another language. This can help accommodate individuals in the audience who may be deaf or hard of hearing, or more familiar with another language, respectively.

https://support.office.com/en-us/article/present-with-real-time-automatic-captions-or-subtitles-in-powerpoint-68d20e49-aec3-456a-939d-34a79e8ddd5f