This doctoral dissertation explores the language-planning role of audiovisual translation through a case study of Flemish public service broadcasting (VRT). VRT has since its establishment been a significant language-planning agent for the Dutch language in Belgium. Areas, like Belgium, where a smaller or minority language is spoken, generally rely more on translation activity than major language areas do. The written standard, therefore, is disseminated to a significant extent through translated texts rather than original texts. Subtitles in many such language areas have become significant disseminators of the written standard and can be an underestimated language-planning tool. This dissertation investigates the use of marked Belgian Dutch lexis in VRT television subtitles over a fifteen year period, and compares it to the common practice in both original and translated literary texts. The Dutch written standard, shared by Belgium, and the Netherlands in Europe, is still exclusively Netherlandic. VRT’s general language policy, since the late 1990s, has gradually become more open to the use of the Belgian national variety. By means of a diachronic analysis of a representative corpus of television subtitles, the extent to which this Belgian variety has recently been used specifically in subtitles (a written text type) is investigated. If VRT increasingly includes Belgian Dutch words and phrases in its subtitles, this practice could provide a counterbalance to the on-going purist approach of the transnational Dutch publishing industry. This could mean that VRT, through its subtitles, is now contributing to the development of a richer, more inclusive Dutch written standard, reflecting the diversity of Dutch with all its national varieties (Netherlandic, Belgian, Surinam, and Caribbean Dutch). This research yields original data in relation to the use and dissemination of Belgian Dutch variants in Belgium, and in doing so illustrates the language planning scope and effects of audiovisual media and subtitles, in general.