Shifting Reading Processes and the Development of Word Reading Fluency

Theories of reading state that the development of word reading fluency is dependent on a shift from a slow letter-by-letter decoding process to the faster parallel processing of the letters in a word. We examined developmental changes in these reading processes based on the accuracy and speed of the reading of isolated words. We also investigated to what extent changes in these within-word reading processes account for individual differences in word reading fluency, conceived as the reading of a series of words. Data from de Jong (2011) were analyzed. Participants were 70 Grade 1 (52.9% boys), 73 Grade 2 (53.4% boys) and 127 Grade 4 Dutch-speaking children (47.2% boys) learning to read in Dutch. Children read sets of one-syllable and two-syllable words. Reading accuracy and reaction time per word were registered. Response mixture modeling was used to separate slow and fast reading times at the word level. Also, measures of word reading fluency and serial rapid naming were included. The proportion of words read in parallel across grades increased for both one- and two-syllable words. Unexpectedly, within grades a clear separation was observed into groups of children reading most words through decoding or in parallel. These changes in reading processes only partly captured differences in word reading fluency development. Independent contributions of the speeding up of each within-word process and the growing importance of serial rapid naming were found. These results suggest the need for a further specification and refinement of theories of reading development.