Dubbing is a specific technique which is part of film translation studies and is most used for audiovisual products (such as films, movies, TV series, cartoons, etc.). There are four different types of film translation: dubbing, subtitling, simultaneous interpretation and the oversound technique (also called voice over).
Dubbing, also known as rerecording or voice acting, is a post-production process in which the original voice of the actor recorded on the stage is substituted with another voice (the one of the dubber), recorded later. It is called a post-synchronization or post-sync technique. It is mostly used in cinema and TV productions, cartoons or advertising (radio or TV commercials).
There are two different types of dubbing: intra-linguistic and inter-linguistic dubbing. The former is used when the director of a film decides that one actor has to be dubbed in the same language: this can happen because the actor doesn’t have proper enunciation or he/she speaks with some regional accent. The latter is used when we need to translate an audiovisual product from a language to another: the main goal is to make the dialogues understandable for an audience which has a different language and a different culture, so that this product can also be sold in other countries.
Dubbing is also used in cartoons, or to make babies, animals or objects talks; it is used even in commercials or films as an off-stage commentary.