I have a two-year-and-five month old granddaughter who came to visit me from Miami last summer. We had a great vacation in both Malaysia and Taiwan. She talked a lot, though I couldn't fully understand what she was talking about. One thing for sure is that she likes to express what is in her mind. This reminds me that learning a language - native or foreign - starts in an early age, and what she heard is what she learned. In a short two week's stay, she coould say 'thank you' and 'how are you' in Chinese accurately. It amazed me a lot.