Abstract:

Previous studies have shown that the amount of vocabularies of children with developmental dyslexia is remarkably lower than that of normal children, thus, it becomes one of the primary indicators for discriminating dyslexia in clinical children develop vocabularies at an extremely high rate in primary school, and a conservative estimate shows that approximately one-third of vocabulary growth is acquired by accidental learning in natural reading. The critical process of this way to learn words, is to infer the word meaning by gathering useful sources base on lexical and contextual cues. Chinese developmental dyslexia typically have deficits in the aspects of morphological- and phonological-related processing, we infer they would be less skilled to derive the word meaning by using lexical information. The first experiment is designed to examine the dyslexic children’s performance of novel word learning in reading.

In Experiment 1, the novel words were embedded into eight sentences, each of which provided a context for readers to form a new lexical representation. Three groups of children were selected as participants, including children with developmental dyslexia (DD), the chronological age-matched children (CA), and reading level-matched children (RL). They were instructed to read sentences containing novel words as their eye movements were recorded. The results showed that, reading times on target words gradually reduced with the increasing of learning stages. Children with developmental dyslexia needed more contexts to begin to decrease for the measures of first fixation duration and gaze duration, and showed a slower decline on total fixation time as compared to age-matched and reading level-matched children. It suggests that more contexts are necessary for dyslexic children to learn novel words in reading.

The insertion of spaces between words, has been proven to be an effective way of improving children’s word learning efficiency. In Experiment 2, we examined whether children with dyslexia were more benefit from word spacing in word learning because of their low-level of reading skills. Three groups of children as the same in Experiment 1 were instructed to read sentences in unspaced, and word-spaced formats. The results showed that all children were benefit from word spacing in word learning, and it was more pronounced for children with- than without- dyslexia. We argue that word spacing may allow readers to form a more fully specified representation of the novel word, or to strengthen connections between representations of the constituent characters and the multi-character word.

Our findings provide robust evidence that Chinese children with developmental dyslexia have lower efficiency of word learning in reading, probably this accounts for their less vocabularies in mental lexicon. The findings also have strong implications for educational practice with respect to reading development with dyslexia.

Key words: developmental dyslexia, word acquisition, word segmentation, Chinese reading