Three and a half years old? Don't be too hard on children. Although education should start with dolls, it is not necessary to start at such a young age. Learning English, in particular, is not easy, so many college English majors can't speak English after four years. Moreover, children are so young that if they are not well guided, it is easy to cause language barriers. Although many linguists say that babies are linguistic geniuses, it should be in some circumstances, whether Chinese or English. Once parents told their children to learn n languages when they were young, but by the time they were seven or eight years old, they couldn't speak all the words. Personally, I think children should learn English step by step, and can't take things that adults can't understand, increase their burden, or even cause psychological obstacles. Therefore, I would like to advise you to be cautious in this matter.