My problem is the same as this previous post! "my ti 84 plus silver edition seems to be on a different language setting because i dont understand anything it says. what do i do to change it back to english?"

Press the [APPS] button. Use arrow to scroll down along the list of apps. Look for apps that have names of languages (Francais, Espanol, Deutch, Dansk, Italiano, Norsk, any european language whose name you can recognize). Once you find the name of a language, highlight it and press ENTER. In the screen that is displayed inviting you to select a language, press 2:English. and press ENTER. The calculator localization should change to the default English language.
To avoid having to do that again, and to save memory spsce, delete the language apps you do not need. delete also the applications that are in those languages (periodic table, Cell Sheets, Science Tools, etc.