What is Vocabulary?

Vocabulary is one of the elements of Evidence based Reading
Instruction, researched in the EFF Read With Understanding
Project. A good vocabulary affects at least two of the other
elements: comprehension and fluency. What does research tell
us about how you acquire vocabulary and what instruction
must do to help you develop the kind of vocabulary knowledge
that will contribute to your reading success?

The paragraph below is an excerpt from the article, A Focus
on Vocabulary, a PREL study. The entire paper can [still] be
located [I hope!] at
http://www.prel.org/products/re_/ES0419.htm

What Is Vocabulary?

Broadly defined, vocabulary is knowledge of words and word
meanings.

However, vocabulary is more complex than this definition
suggests. First, words come in two forms: oral and print.
Oral vocabulary includes those words that we recognize and
use in listening and speaking. Print vocabulary includes
those words that we recognize and use in reading and
writing. Second, word knowledge also comes in two forms,
receptive and productive. Receptive vocabulary includes
words that we recognize when we hear or see them. Productive
vocabulary includes words that we use when we speak or
write. Receptive vocabulary is typically larger than
productive vocabulary, and may include many words to which
we assign some meaning, even if we don't know their full
definitions and connotations, or ever use them ourselves as
we speak and write (Kamil & Hiebert, in press).