Closed captioning is a text-based transcription of a television program that runs simultaneously with the show. It is generally used by people who are hard of hearing or completely deaf. It appears at the bottom of the screen and represents the things that the people and characters are saying. You don't need to purchase additional equipment to enjoy closed captioning--most televisions already support it.
Press the "Menu" button on your television's remote control. This will display the settings menu of your television on the screen. Here you can change a wide variety of options, including picture controls and audio settings, as well as settings detailing exactly how your TV works.
Use the arrows on your remote control to navigate to "Preferences." Press "Enter" to select it.
Use the arrows to navigate to the "Closed Captioning" option. It's called something different on every television, but it all means the same thing. For example, on a Toshiba television the option is called "Basic CC Mode."
Highlight the option and press the "ENTER." It will begin working almost immediately.
Press the "Menu" button one more time to exit the menu. You will now be returned to the program you were watching, complete with closed captioning subtitles.