I just finished a test today with my most junior afternoon class. Maybe about 6 or 7 years old, about 12 of them. Very basic English - half of them can't even answer the "What is your name" question.
However, there is one question which I've never known a student, no matter how young, how stupid, how limited the English, ever not get. Show them a picture of a monkey and they immediately cry "monkey!"
So no matter what my failings as a teacher, after a year of this I am confident I will be able to leave behind well over 100 children, all of whom know how to say "monkey" in English.