At what stage is your group?  How souped up is your code?

water) prompting for English, splitting, joining, printing

bronze) translating with just known words only

silver) translating and adding user given new word translations
   double check that they are really being added by
   >>> print(eng2fr)

golden level) 
   translating and asking the user for each unknown word,
   but user can offer a translation (to add to dictionary) OR
   user can answer that don't know(& don't add to dictionary)
     so just let the English word slide through.