A method for initiating by voice display of closed captions for media content, comprising: at a server system, including a processor and memory storing at least one program (728, 760) for execution by the processor, wherein the server system includes a device registry, the device registry keeping a record of a plurality of display devices, electronic devices and cast devices, wherein the electronic devices and the cast devices are associated with each other via a user account in a virtual user domain: receiving a voice message from one of the plurality of electronic devices; determining that the voice message is a first closed caption initiation request, wherein the first closed caption initiation request includes a user voice command to initiate closed captions and a user voice designation of a display device playing the media content for which closed captions are to be activated, wherein the user voice designation of the display device includes a description of the designated display device; in accordance with the designation of the display device, identifying, in the device registry, the cast device associated in the virtual user domain with the electronic device and coupled to the designated display device, wherein the cast device is configured to execute a media play application for controlling the designated display device to display media content received from a media content host, identifying in the device registry the designated display device among the plurality of display devices according to the description of the designated display device; and sending by the server system a second closed caption initiation request to the cast device coupled to the designated display device, thereby enabling the cast device to execute the media play application that controls the designated display device to turn on the closed caption of media content that is currently displayed on the designated display device and display the closed caption according to the second closed caption initiation request. receiving a voice message from one of the plurality of electronic devices; determining that the voice message is a first closed caption initiation request, wherein the first closed caption initiation request includes a user voice command to initiate closed captions and a user voice designation of a display device playing the media content for which closed captions are to be activated, wherein the user voice designation of the display device includes a description of the designated display device; in accordance with the designation of the display device, identifying, in the device registry, the cast device associated in the virtual user domain with the electronic device and coupled to the designated display device, wherein the cast device is configured to execute a media play application for controlling the designated display device to display media content received from a media content host, identifying in the device registry the designated display device among the plurality of display devices according to the description of the designated display device; and sending by the server system a second closed caption initiation request to the cast device coupled to the designated display device, thereby enabling the cast device to execute the media play application that controls the designated display device to turn on the closed caption of media content that is currently displayed on the designated display device and display the closed caption according to the second closed caption initiation request.