Here's a story about some very young but very sharp Thai and Chinese students.
I interviewed for a math and science teacher position. They sent me into the classroom for a short demonstration lesson. Fortunately I brought my math handouts. But they didn’t want to see how well I teach math or science. They wanted to know how well I engage the students and how well I keep them under control. I introduced myself, told them about my travels, and opened the floor for questions.
One of them asked, “ Do you have a girlfriend?” “No.” Another followed this with, “Are you sure you don’t have a girlfriend?” “I’m sure.” A third one asked, “Do you have a boyfriend?” One asked me who my favorite superhero was. I don’t have a favorite superhero, so I just said Ironman. They said, “Ironman 1, 2, or 3.” Then one said, “Ironman 3 is the best.” I said, “I agree. I watched Ironman 3 on my laptop a few days ago.” One of them asked me what’s my favorite country. I said Thailand. Another one said, “Don’t you like America?” I said, “Of course. America is my favorite country. Thailand is #2. Thailand would be your #1 and another country would be your #2”
They’re 10 years old and they don’t speak English as their native language, but they were asking me sharp questions with complete correct grammar and very good pronunciation and they understood everything I said. Similar experiences when I taught kindergarten in China. One of the rules for the children was "Do not speak Chinese during the English lessons." The punishment was to sit in the bedroom alone and silent. Of course, children want to be with other children and play, so they dreaded this punishment. The facilities manager came into my classroom during one of my lessons to talk to my team teacher. He didn't know a word of English. The children jumped out of their seats, shook their finger at him, and then pointed to the bedroom. They shouted, "No Chinese! Go to the bedroom!"
The most important thing I have learned about young learners is that they are much more perceptive than we think.