Context: If he heard that we talk about anything going out , he will start to asking to go " tai tai ( going out ) " . He will be talking loudly and happily in his own language if I am driving him out in my car . Whenever I tried to hide from him and he could not find me , he would shout out loudly for " TU - TU ( auntie ) " .

Question: What may be the reason that he talks in his own language ?
Options:
0. Because he is in the car .
1. Because he wants to go out .
2. Because he is a baby .
3. None of the above choices .
Answer: 2