It was in the 1920s when the first set of seiyus created voice-only performances and dramas on the radio. However, even in earlier forms of theater, the popularity of voice actors was not widespread. Before then, people did not need anyone creating voice-overs or dubbing except for narrating stories in the theater. The birth of the seiyuu happened only after the popularity of the radio soared in Japan.
The latter is a common western equivalent of the seiyuu. The term seiyuu can also be interchanged with the acronym CV which directly means character voice. The intensity of the voice, the pitch, and even how much it quivers can determine the success of a seiyuu in expressing the correct emotion depending on the story which is being told. This is much harder because there must be a distinct difference between joy, sadness, surprise, anger, and all other range of emotions involved in telling stories. However, a voice actor or a seiyuu uses only his or her voice to express a feeling. It is usual for actors to use actions and facial expressions to express emotion. For those who are wondering why voice acting can be quite harder than normal acting.
