Be alert but not alarmed... the quiet child..
Quiet children are clever. In some cases, they have learnt the art of not discussing their issues at home. There can be a variety of reasons for this, but one common reason which is evident through counseling is that sometimes parents are great talkers and the child cannot compete, especially if parents have a strong personality. Children stay quiet because it is too hard to compete in conversation. Also, they feel safe as they are not failing to say the wrong thing.
When you listen to a child, be still and give eye contact. This gives them emotional space to process their thoughts. Talking to them with a gentle, calm voice reassures them that there will be no reaction to what they say and how they say it. Often finding a quiet space perhaps before bed, gives the child more opportunities to talk about their day.
I recently walked past a group of boys very actively engaged in conversation with each other. As I turned to notice them I was surprised that the ring leader who had much to say was a little boy who does not talk much with his family. In fact, he was receiving counselling for his quiet disposition. He smiled at me looking somewhat coy and said, " Yes Mrs Smith. You see I can talk when I want too".
Children engage better with us if they are not overwhelmed by our style of parenting or expect a reaction. Gentle always wins the day.