mina mohammadi nouri

Expressive vocabulary plays a vital role in child language development, and its assessment can be one of the essential indicators to identify language developmental delay, especially in children with Down syndrome. We developed a list of expressive vocabulary and compared the size and class of expressive vocabularies between typically developing and Down syndrome children.

Expressive vocabulary of 150 children was examined in this study. A total of 120 typically developing Farsi-speaking children (in four age Groups, with a 6-month interval) and 30 children with Down syndrome (aged 24-48 months) participated in this study. The parents of the children filled out the form that included 636 words from different vocabulary classes. These classes were based on studies that investigated language development in Farsi-speaking children.

The expressive vocabulary size in Farsi-speaking children was significantly higher than in Down syndrome children (P≤0.001). There was no statistically significant difference between boys and girls regarding expressive vocabulary size in two Groups of children. The size of nouns in all age Groups is more than other classes, and the size of conjunctions in all age Groups is less than the other ones. A direct correlation was found between age and the size of expressive vocabulary.

According to the study findings, the list of expressive vocabulary can detect delays in developing expressive vocabulary.

Many studies have claimed that speech perception in dyslexic children is impaired in comparison to normal children in a way that dyslexic children are weaker in the discrimination and identification of phonemes. In this research, we study speech perception, syntactic skills, and phonological processing in the normal and dyslexic Farsi-speaking children.
We examined the speech perception in 30 normal and 18 dyslexic children, using speech identification task in 3 continua of voice onset time (VOT) in [ba-pa], [da-ta], and [ga-ka]. We also studied 2 other skills to examine the processing of phonological information and syntactic skills. We used the nonword repetition test and passive sentence comprehension, respectively. To compare the data, the Mann-Whitney U test, t-test, and logistic regression were used.
Dyslexic children in speech identification task performed similarly to normal children in all 3 continua (P=0.81, 0.87, and 0.58); but, in the nonword repetition test, they were significantly lower than normal children (P=0.01), and in the passive sentence comprehension task, there was no significant difference between normal and dyslexic children (P=0.12).
The results of various studies for speech perception and linguistic abilities in dyslexic children are contradictory. They are mostly related to the tasks that have been used. Therefore, more studies in the future are suggested.