Differences in growth rates and vocabulary development manifest themselves early in a child’s life and seem most closely correlated with socioeconomic status (SES). For instance, one study showed that three-year-old children of professional parents had larger vocabularies than children of parents on welfare (Hart & Risley, 1995). This finding is less shocking when considered in light of another: Children in professional homes heard 382 words an hour while children raised in welfare homes heard an average of 167 words an hour. In a month, the difference in words heard was 1,100 (professional) to 500 (welfare). Hart and Risley’s findings support Becker’s conclusion that a major factor in the school failure of “disadvantaged” children was inadequate vocabulary knowledge (1977).

Of even greater concern is the belief of many scholars that, once established, differences in vocabulary knowledge are difficult to eliminate and as a result continue to manifest themselves as students move through school (Coyne, Simmons, & Kame’enui, 2004; Hart & Risley, 1995). As Blachowicz et al. (2006) contend:

There is a gap in vocabulary knowledge between economically disadvantaged and economically advantaged children that begins in preschool and is an important correlate of poor school performance. (p. 526)

Consider the following results from some seminal studies in the field:

  • First-grade children from higher SES groups know about twice as many words as lower SES children (Graves, Brunetti, & Slater, 1982; Graves & Slater, 1987).
  • High school seniors near the top of their class know about four times as many words as their lower-performing classmates (Smith, 1941).
  • High performing third graders had vocabularies about equal to the lowest-performing twelfth graders (Smith, 1941).

The end result is that enriched environments promote vocabulary development. Good readers read more, which in turn helps them become even better readers with even larger vocabularies. Poor readers read less, which contributes to their becoming poorer readers with more limited vocabularies. In effect, “the rich readers get richer and the poor readers get poorer.”