Answer to Question 1
A caregiver gives less attention to a raggedly dressed child with unkempt hair; a teacher routinely disciplines girls more harshly than boys because she expects more of them; a parent secretly admires his son for fighting but disapproves of that same behavior in his daughter.
Answer to Question 2
Because it is high-pitched and sing-song, it may hold the infant's attention and aid the infant's focus on speech or it may soothe. A few infants prefer lower speech sounds. The practice can be frowned upon in some cultures.