Vocabulary Intervention and Reading Comprehension

Vocabulary, the knowledge of what words mean, is central to understanding any language. What words mean in context depends on what the speaker or writer intends to convey. With regard to everyday conversations as well as fiction, essays and literary pieces, words can oftentimes carry a different meaning. Years ago, Jose Carillo wrote in an essay in the Manila Times the following: "Formal grammar, semantics, and structure can only lay the bare foundations for English proficiency. Only when we have become adequately conversant with its idioms can we really say that we know our English." Being conversant with American idioms can only be achieved by increasing exposure to the culture that uses these expressions. Not being familiar with idioms can be frustrating when reading stories and novels with an American cultural setting.

Still, even with exposure to an American setting, one stumbling block remains. In order to read to learn, knowledge of the academic vocabulary of the language used as medium of instruction is necessary. These are words often not used in daily conversations but appear quite frequently in textbooks across various disciplines. Having a poor academic vocabulary can be a serious hindrance in learning mathematics and the sciences, for example. Understanding a textbook or a lecture requires comprehension or knowledge of the words used. In this area, even children who have done very well in their reading classes during the early elementary years can find themselves struggling in both middle school and high school if their academic vocabulary has not kept pace with the level of material being tackled inside the classroom.

Developing academic vocabulary should be a regular task. Falling behind requires intervention and interventions are usually difficult and unsuccessful. To measure the effectiveness of an intervention targeting academic vocabulary, Lesaux and coworkers went to 14 urban middle schools in California and monitored the literacy and language skills of about 1500 students:

The intervention was 20 weeks long (45 minutes per day):

The results are quite promising with regard to the direct target of developing academic vocabulary:

Graph drawn from data taken from
Am Educ Res J April 25, 20140002831214532165
The difference between pretest and post test scores in an Academic Word Mastery Exam divided by the standard deviation in the pretest scores is shown in the above graph. EO (English Only) are students who belong to homes where only English is spoken while LM (Language Minority) are students who belong to homes where a language other than English is used.

Unfortunately, the same progress is not evident when it comes to a reading comprehension exam:

Graph drawn from data taken from 
Am Educ Res J April 25, 20140002831214532165
Reading comprehension appears to require more. The authors of the above study are optimistic, saying that the small effects on reading comprehension simply mean that the intervention must be made longer and more frequent. Reading comprehension is really an assessment on how well vocabulary knowledge transfers to literacy. It is true that this may take more time and effort....