While children from different backgrounds typically develop language skills around the same age, the subsequent rate of vocabulary growth is strongly influenced by how much parents talk to their children. Children from professional families (who were found to talk to their children more) gain vocabulary at a quicker rate than their peers in working class and welfare families.


Examine language development in young children and the effects of home experiences on children’s development.


Record and analyze verbal interactions in 42 families, from the time the child was 10 months old to 3 years of age. Three types of families were included: professional families (parents were professors), working class families and families who were on welfare. Families were observed for one hour each month for almost two and a half years. Children ranged in socio-economic status, sex, birth order, number of siblings and family structure. All families were considered “well-functioning”.

Major Findings

  • Children from all three groups of families started to speak around the same time and developed good structure and use of language.
  • Children in professional families heard more words per hour, associated with larger cumulative vocabularies.
  • In professional families, children heard an average of 2,153 words per hour, while children in working class families heard an average of 1,251 words per hour and children in welfare families heard an average of 616 words per hour. Extrapolated out, this means that in a year children in professional families heard an average of 11 million words, while children in working class families heard an average of 6 million words and children in welfare families heard an average of 3 million words. By kindergarten, a child from a welfare family could have heard 32 million words fewer than a classmate from a professional family.
  • By age three, the observed cumulative vocabulary for children in the professional families was about 1,100 words. For children from working class families, the observed cumulative vocabulary was about 750 words and for children from welfare families it was just above 500 words.
  • Children in professional families heard a higher ratio of encouragements to discouragements than their working class and welfare counterparts.

Policy Implications

Based on their research, the authors reached the following key conclusions: