my son 20 months old.he is talking himself like amma nanna atha thatha...like meny more sounds.he wont cal us like to me amma...he wont cal like nanna to his father.when we cal by his name...he won't respond...not showing...eye contact with us.he will recognise all songs rhymes....sounds....very quikly....for sounds...he will respond very speedly....bit whe we cal not responding not listening our words....he is too active....is it ok or any problm...pls tell me