E-learning comprises all forms of electronically supported learning and teaching. The information and communication systems, whether networked learning or not, serve as specific media to implement the learning process. wikipedia.org

"Narration is the act of telling a story, usually in some kind of chronological order."

Voice-over is a production technique where a voice, that is not part of the narrative (non-diegetic), is used in a radio, television production, filmmaking or other medium.

Voice acting is the art of providing voices for animated characters (including those in feature films, television programs, animated short films, and video games) and radio and audio dramas and comedy, as well as doing voice-overs in radio and television commercials, audio dramas, dubbed foreign

Public speaking is the process of speaking to a group of people in a structured, deliberate manner intended to inform, influence, or entertain the listeners. It is closely allied to "presenting", although the latter has more of a commercial connotation. wikipedia.org

Audio editing is the process of taking recorded sound and changing it directly on the recording medium (analog) or in RAM (digital). wikipedia.org