Vocabulary refers to the words children need to know to comprehend and communicate.
Oral vocabulary is the words children recognise or use in listening and speaking.
Reading vocabulary is the words children recognise or use in reading and writing.

Vocabulary is the most powerful predictor of reading comprehension. It’s clear that knowledge of word meanings is essential if a reader is to understand what they have decoded in a text.

Beyond its significance for reading, word knowledge influences thinking, speaking, and writing throughout life, and perhaps even cognitive development.

The National Reading Panel included vocabulary as an essential component of a comprehensive reading program, while the US National Assessment of Educational Practice reports also reiterate the significance of vocabulary in reading attainment.

On school entry, approximately 20% of Australian students are deficient in the vocabulary domain. In disadvantaged areas, this percentage rises to nearly 30%. Early vocabulary gaps tend to persist over time, and are a factor in further disparities in students’ subsequent educational careers.

When it comes to vocabulary acquisition, the early years are critical. Early vocabulary acquisition has been demonstrated to be particularly important because of its relationship to subsequent reading progress. There is evidence that improving vocabulary before age six is very highly associated with literacy success in late primary school and even into mid secondary school.

It is rare for students to struggle with reading comprehension if their decoding and vocabulary are well developed. While many children will broaden and deepen their vocabulary by wide reading, others will not. Unfortunately, many children with delayed vocabulary are either not detected, or are not provided with adequate assistance. These students do not catch up without intensive, extended levels of intervention. Students with vocabulary deficits can be readily detected as part of an initial screening process, with intervention at the beginning of school producing far better outcomes than interventions later in the first year.

“There is much evidence—strong correlations, several causal studies, as well as rich theoretical orientations—that vocabulary is tightly related to reading comprehension across the age span.”
“Unless children develop strong vocabularies early in life and continue to deepen and broaden their vocabulary knowledge throughout the schooling years, they will predictably face difficulty in understanding what they read, will not use advanced and mature words in their writing, will have problems with academic subjects, will perform poorly on national achievement tests, and will fall steadily behind their more vocabulary-proficient peers.”
“Students with low levels of initial vocabulary knowledge likely require supplemental intervention in addition to classroom-based vocabulary instruction in order to make gains similar to those of students with higher levels of initial vocabulary knowledge.”
“Those who enter 4th grade with significant vocabulary deficits show increasing problems with reading comprehension, even if they have good reading (word identification) skills. The available evidence does not suggest a substantial “catching-up” process, but rather a continuing slippage relative to those with average and above-average achievement.”


A randomised controlled trial, Clarke, Snowling, Truelove, and Hulme (2010), reported that enhancing children’s vocabulary development using explicit instruction methods was more effective at improving reading comprehension than was teaching the students comprehension strategies.

Research reviews have emphasised a multiple strategy approach is necessary for vocabulary building, including:

  • Direct instruction/explicit teaching
  • Guided instruction
  • Multiple encounters of the same words in varying contexts
  • Working with a partner or small group
  • Story retelling
  • Use of props or concrete objects
  • Comprehension and vocabulary discussion, and
  • Ensuring vocabulary instruction is embedded in all curriculum areas.

(Sinatra, Zygouris-Coe & Dasinger 2011; Lenfest & Reed 2015)


Clarke, P., Snowling, M.J., Truelove, E. & Hulme, C. (2010).
Ameliorating children’s reading comprehension difficulties: A randomised controlled trial.
Psychological Science, 21, 1106-1116.

Hay, I. & Fielding-Barnsley, R. (2009).
Competencies that underpin children’s transition into early literacy.
Australian Journal of Language and Literacy, 32(2), 148-162.

Hirsch, E.D. (2013).
Primer on success: Character and knowledge make the difference.
Education Next, 13(1).

Lenfest, A. & Reed, D.K. (2015).
Enhancing basal vocabulary instruction in kindergarten.
Learning Disabilities Research & Practice, 30(1), pp. 43–50. DOI: 10.1111/ldrp.12050

Loftus, S.M. & Coyne, M.D. (2013).
Vocabulary instruction within a multi-tier approach.
Reading & Writing Quarterly: Overcoming Learning Difficulties, 29(1), 4-19.
Doi: 10.1080/10573569.2013.741942

National Assessment of Educational Practice (2012).
The nation’s report card: Vocabulary results from the 2009 and 2011 NAEP Reading Assessments.
Institute of Educational Sciences, Washington, DC.

National Reading Panel (2000).
Teaching children to read: An evidence-based assessment of the scientific research literature on reading and its implications for reading instruction.
Department of Health and Human Services, Jessup, MD.

Reilly, S, Wake, M, Ukoumunne, O, Bavin, E, Prior, M, Cini, E, Conway, L, Eadie, P, & Bretherton, L 2010.
Predicting language outcomes at 4 years of age: findings from Early Language in Victoria study.
Pediatrics, 126(6), 1530-1537. DOI: 10.1542/peds.2010- 0254

Sinatra, R., Zygouris-Coe, V. & Dasinger, S. (2011).
Preventing a vocabulary lag: What lessons are learned from research.
Reading & Writing Quarterly, 28(4), pp. 333-357.

Snow, PC 2016.
Elizabeth Usher Memorial Lecture: Language is literacy is language – Positioning speech-language pathology in education policy, practice, paradigms and polemics.
International Journal of Speech-Language Pathology.
DOI: 10.3109/17549507.2015.1112837

Taylor, C.L., Christensen, D., Lawrence, D., Mitrou, F. & Zubrick, S.R. (2013).
Risk factors for children’s receptive vocabulary development from four to eight years in the longitudinal study of Australian children.
PLoS ONE, 8(11), 11-20.