My thoughts on: Age Ability from Age Zero, by Shinichi Suzuki, p. 4
Isn't he cute? He probably even says, "KO- Nee- CHee-Waa" without any prompting from his mother. How do I know this? Well, it's because way back when he was a baby, he was listening to his mama and papa talking in Japanese. In fact, he's even been listening since the womb.
He probably won't give a lot of evidence that he understands much of it until his points and grunts don't cut it anymore. He'll have to speak if he wants a little more Nori or tofu. Pretty soon, he'll be corrected: here and little and there a little, until he's a fully communicating Japanese boy.
Suzuki discovered this amazing thought, and it was totally a "gestalt" for him-- an "ah ha" moment. This helped him discover the "mother-tongue approach" to learning.
So, the next time your children say something, consider this: they heard it-- probably from you.