http://www.prel.org/programs/rel/prodserv.asp

A Focus on Vocabulary explores vocabulary development as a component of
reading comprehension by describing what research says about how students
acquire vocabulary and about instruction that helps students develop the
kind of vocabulary knowledge that will contribute to their reading success.
It begins with a definition of vocabulary and continues with discussion of
why vocabulary is important in reading comprehension, what “knowing” a word
means, key instructional strategies, and issues related to vocabulary
development for English Language Learners (ELLs). A Focus on Vocabulary is
the second in the Research-Based Practices in Early Reading series published
by the Regional Educational Laboratory at PREL. The document is available
online only and can be accessed in HTML (116K), Color PDF (5.5M) or Black &
White PDF (2.5M) format. Users are asked to complete a survey to access this
free, online document.