The Presence and Progression of Rare Vocabulary Across Elementary Grades and Between Text Types

• In Event: Word Exposure and Vocabulary in Action: Exploring Frequency, Lexical Pragmatics, and Their Relationships

Abstract

Purpose
This study examines rare vocabulary in narrative and expository texts at Grades 1, 3, and 5. The focus lies in the amounts and features of rare vocabulary in the two text types at these grade levels.
Perspective
Although a small percentage of the English lexicon accounts for most words in text (Zipf, 1935), it is rare words that typically define the content of narrative and expository texts. Perspectives on which rare words should be taught are limited (Nagy & Hiebert, 2012). Building and validating a vocabulary selection model requires knowledge of the progression, amount, and features of rare words in narrative and expository texts at critical milestones across the elementary grades.
Method/Data Sources
We collected a 50,000-word random sample for each grade and text type from a database of 12,000 digitized school texts (8 million words), which included passages from core reading, leveled, and decodable programs and trade books. The three milestones targeted Lexile levels (L) recommended by the Common Core State Standards (National Governors Association, 2010): (a) Grade 1: 310L – 400L; (b) Grade 3: 610L – 700L; and (c) Grade 5: 910L – 1,000L.
The Word Zone Profiler established distributions of words in three frequency zones, which are based on predictions of appearances per million words of text (Zeno, 1995): (a) Highly frequent: 100+; (b) Moderately frequent: 10 - 99; and (c) Rare: < 10. For each grade and text type, analyses established percentages and features of rare words (number of letters, age of acquisition (AoA)).
Results
Rare words accounted for a substantial percentage of unique words in both text types but more so in narrative texts across the grades: Grade 1: N = 29, E = 24; Grade 3: N = 34, E = 26; and Grade 5: N = 39; E = 32. Differences in mean word length by text type were similar but means increased by grade level: Grade 1: N = 5.8, E = 6.2; Grade 3: N = 6.9, E = 7.1; and Grade 5: N = 7.3; E = 7.7. AoA was similar for text types at Grades 3 and 5, with higher means for the latter grade: Grade 3: N = 8.0, E = 8.1 and Grade 5: N =9.2, E = 9.4. At Grade 1, AoA was somewhat higher in expository than narrative texts: N = 6.9, E = 7.3.
Scientific Contributions
Vocabulary is a strong predictor of comprehension (Cromley & Azevedo, 2007). This analysis shows that elementary students encounter many rare words in texts, especially in Grade 1 where AoA is high relative to chronological age. Available data on student proficiencies indicate that many students are challenged in recognizing rare vocabulary, such as that found in the study texts, particularly at first grade but also beyond (Author, 2019). Extension and application of findings from studies such as this one are essential if less-than-proficient readers are to receive vocabulary instruction that lessens the comprehension gap.

Authors

• Elfrieda H. Hiebert, TextProject
  Presenting Author

• Alia Pugh
  Presenting Author

• Devin Kearns, University of Connecticut
  Presenting Author