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 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

Audio post production is the general term for all stages of production happening between the actual recording in a studio and the completion of a master recording. It involves, sound design, sound editing, audio mixing, and the addition of effects. wikipedia.org

Radio broadcasting is a one-way wireless transmission over radio waves intended to reach a wide audience. wikipedia.org

Digital media is any media that is encoded in a machine-readable format. wikipedia.org