If you are going to teach it with the child who is 7 year old, you are going to use the word that can easily understand or comprehend them, but it really depends on the child if the child is not interested they will not easily understand it coz we all know that age is not the age that a child will give time to understand it. There is a child who are very curious but only few.
I think its hard to teach the child who is 7 years old because the set up their mind is on playing toys and on playing on friends but if you want to teach them you must use appropriate word where they can understand it easily and clearly. Lastly, I think you would have diffuculties in teaching them but if they some interest on it they will really understand it.