You can have two cases one - the language is defined, and two - the language is not defined

Same for both

  1. Go to the Drink! folder
  2. Open languages.ini
  3. Look if there is a line where is your language in [] if yes it is defined, else it isn’t.

    Is defined

  4. Open confing.ini
  5. Change the language = czech to language = <your language>

    Is not defined

  6. Go to the end of the file
  7. Add a new line
  8. Write 
    [<your language>]
title = <title of the pop up window>
text = <text of the pop up window>

    eg. You want english so you write

    [english]
title = Drink!
text = You must drink now!
  9. Go to the sounds folder.
  10. Add a wav file with the name of your language eg. english.wav - that is the sound that is played when you must drink.