前回書いた高校生が書きそうな英文を brush up した英文に書き直してみます。
Young children in Japan should not study English. There are two reasons for it.
First, they should study Japanese more. There is no evidence that the earlier they strat studying English, the better they can use it.
Second, even if they can use English very well, Japanese people who can't use Japanese well are not able to get a good job. Actually, there are many Japanese young people who can't speak it in a polite manner.
In conclusion, Japanese childen had better study English after they master Japanese.