With direct vocabulary instruction students’ comprehension increases. Building Background Knowledge for Academic Achievement: Research on What Works in Schools (Marzano, 2004).
Common Core Focus on the Teaching of Academic Vocabulary • http://engageny.org/resource/common-core-in-ela-literacy-shift-6-academic-vocabulary/
Concerns about teaching vocabulary: • Nagy and Anderson found 88,500 terms in grades 3-9 textbooks (1984). • Most of these (85%) are tier 3 words. Half of these terms would be encountered only once in the life of an avid reader. Research has shown that giving students lists of words, having them look up the definition, and asking them to memorize them for a test does not teach students vocabulary.
Marzano Video http://www.ascd.org/research-a-topic/building-academic-vocabulary-2.aspx