TIT
I teach at a private school where only the rich can afford. Everyone knows students acquire English when they want to. The real fact is that yes, the parents want the best for their "little darlings", but do absolutely nothing to make sure they are doing their part as parents to help in the process, eg; checking homework, asking questions, etc. After living here almost two years, I have yet to see or hear a Thai discipline a child for anything. My analogy is they are kind of like an animal. They have them, then they are on their own to more or less raise themselves. That is the Thai culture. Children are a product of their parents and they learn good or bad habits from them. I have had only one parent talk to me about their child, even though I have wrote many bad reports on the report cards concerning their children's behaviour. The principal at my school told me that most, if not all the parents speak English. So, it isn't a fact of being shy or not understanding English. I believe it is a fact of just not caring what their children are doing.
If I would have ever gotten a bad report from my school, or anyone else for that matter, about a problem they were having with me, I wouldn't be able to sit down for a week. This is not the west and attitudes about education and behaviour are much different, but it is my belief that sometimes a good old fashioned "ass whipping" is in order.