1. A voice-controlled data system comprising: a data storage unit including a plurality of media files, at least one of the media files including associated file identification data; a vocabulary generating unit for generating phonetic data corresponding to the file identification data, the phonetic data being supplied to a speech recognition unit as a recognition vocabulary, where one of the media files is selected according to a recognized speech control command on the basis of the generated phonetic data; and where the file identification data include a language identification part for identifying the language of the file identification data, and where the vocabulary generating unit generates the phonetic data for the file identification data of a media file based on its language identification part.