Spelling transparency and its impact on dyslexic and unimpaired children's memory for words.

The phonologically transparent Persian orthography is normally transcribed with two distinct spellings; words spelled with vowels (letters) transcribed as a fixed part of the spelling (transparent) and words spelled with vowels (diacritics) omitted (opaque). Three groups of Persian readers, namely developmental dyslexics (n=29, mean age=9.4, SD=1.4), unimpaired readers matched on age (n=49, mean age=9, SD=1.3), and reading age (n=23, mean age=7.2, SD=0.4) with the dyslexics performed on a short-term memory verbal test. The time taken to read aloud lists of words with opaque and transparent spellings, the errors made on reading the words in each list, and the number of correctly recalled words in each list was subjected to statistical analysis. The results showed that transparent words as a whole were read more accurately than opaque words. However, recall of words was best for opaque words for the older group of unimpaired readers compared to the transparent words, while the opposite was true for dyslexics and unimpaired reading age matched participants. The implications of these results are discussed.