I'm assuming this users response here but I think they mean that if a button isn't used in any of the the menus throughout the game, like clicking the left joystick button, and you change it to something like this

*click and hold left joystick

>if the joystick button is depressed - temporarily disable the normal function of some other keys in anticipation for a code input

*while holding left joystick button, hit a b a b, or an equivalent depending on the system. This is the key sequence, or code.

>this triggers all menus henceforth to be voiced out loud for the player. Another button sequence/code can be used to specifically voice only the current menu, and not all menus. Ex. ' depress and hold left stick button - hit a a b b - release left stick button. Current menu is now read to the player '

Now if you really want to go an extra step and make an impressive impact, you can have the programmers set up a small memory for which menus the players profile wants to be voices. Lets say, a low vision player only needs a few of the specific menus read to them. A third key sequence or code can be used by the player to say ' Remember this menu and always read it'. Now the player doesn't need to hit a code every 2 minutes of game play, and they don't need to listen to voiced menus that they don't need to hear. A fourth key sequence can be used to reset all menus set to voice activate. Print the key sequenced codes on a Braille sheet and insert that into the jewel cases of the game, or mail it to customers if they email a specific address.