Estimates of student vocabulary size vary dramatically
(Anderson and Freebody 1981). Using a body
of words gathered from school materials and textbooks (Carroll, Davies and
Richman 1971), they grouped related words into families by judging whether a
student who knew the meaning of only one of the words in a family and could
infer the meanings of other words in the family. A word family is a group of words related in meaning. From this analysis it was determined that
there are about 88,500 distinct word families in printed school English and
that an average 12th grader probably knows about 40,000 of them
(Nagy and Anderson 1984). A root word is
a single word that cannot be broken into smaller words or parts. There are about 17,500 root words known by
students in Grade 12. Of these root
words, they estimate that about 15,000 words are known well by a majority of
students (Dale and O’Rourke 1981).
Children
through Grade 6 typically acquire about 800 to 1,000 root-word meanings per
year. By the end of Grade 2, students
know an average of about 6,000 root word meanings (Biemiller 2005).
In Grade 1
the number of derived words that students acquire is three times the number of
root words (Anglin 1993).
About 2
words per day, or 10 per week can be taught directly (Diamond and Gutlohn 2006).
Profound
differences exist in vocabulary knowledge among learners. Focusing vocabulary instruction on acquiring
root words is an effective way to address the large number of words that
students must learn each year (Diamond and Gutlohn 2006).
Vocabulary
seems to occupy an important middle ground in learning to read (National
Reading Panel 2000). Vocabulary occupies
an important position both in learning to read and in comprehending text:
readers cannot understand text without knowing what most of the words mean
(National Reading Panel 2000). To
comprehend text, students require both fluent word recognition skills and an average
or greater than vocabulary.
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