How can you teach a child words but not how to read. They could learn words but to understand them they need to learn how to read so it makes more sense. You could read the word "the" or the word "store", but how would the understand what it means to put it together if they don't hear it in a sentence like "I went to the store today to buy milk." Words mean nothing without context.
To teach them about history I think is important, they need to learn about what has happened in the past so they can learn how to prevent the same things from happening again and to get a better understanding of where we all came from. We need to teach them about different cultures and society so they can learn to interact with different people that are not like them. If you don't show the child that people are different and they think everyone is like them, it will be a rude awaking when they meet someone else for the first time. .
Rousseau doesn't want to teach Emile other languages. I believe that it is the best time to learn when you are young. A young mind is very impressionable and this is the best time to take everything in. When a child learns a sport like football or gymnastics, they will try and move or play because when they are young they have no fear. A child learning a back handspring when they are young can eventually do one perfectly because they are not afraid to try it. Now if you teach an adult to do a back handspring they are more hesitant and are more fearful because they know what could happen to them is they put their hand down wrong. They know the consequences of getting hurt where a child doesn't. That why I think when you are young is the best time to learn. .
More and more in this day and age we are thinking that as well. When I was I was in school we learned a language starting in seventh or eight grade. I know I had a lot of trouble understanding and grasping the concept of the language at that age.