1)Put healthy snacks in the vending machine (less unhealthy snacks)
2) Remove vending machines ( remove the option of unhealthy snacks)
Rroughly half to 60% can speak it well enough to hold a basic conversation
They were allowed to rejoin if they accepted the 13th amendment. It was one of the reconstruction amendments that ended slavery and gave led to African-Americans getting their voting rights and their freedom.If they wouldn't accept it they wouldn't be allowed back.
The United States and the Japanese.
That is a poor convincer so your best bet is not doing that