Thamizhini knows how her Appa's bike will go by making sound. We used to show her when her Dad starts to office and in the evening she used to go for a round once her Dad is back from Office. So she knows about bike and the noise that makes. Even by sitting at home in the morning, she will hear her Dad's bike sound when he starts to office and says Appa... Appa... and makes the below mimic. Check out the below video.. an upcoming mimicry artist.