Background and Aim: Studies have shown that most children before age 4 are able to comprehend and express wh-question. In the Persian language, a case study has confirmed these results. The aim of this study is to evaluate the ability of 4-6 year olds to comprehend and express wh-question.
Methods: Seventy two 4-6 year-old Persian-speaking children were selected randomly. Wh-words consist of: what, where, who, why, and when. In the part of comprehension subjects answered questions about two pictures, and in the part of expression they asked questions elicited by a speaking puppet about four pictures. Descriptive analysis and student&aposs t-test were used for data analysis.
Results: In comprehension 4-6 year-old children gained the complete score (2) with SD=0 in all wh-words. However, 4-5 year old children gained the score of 1.89 with SD of 0.32 for the word when. In expression, independent t-test showed the maximum score of 3.52 with SD of 0.84 related to questions with who. 5-6 and 4-5 year old subjects had significant differences in questions with what (p=0.005), where (p=0.003), who (p=0.012), and when (p<0.001). Most errors were expressed in question with when.
Conclusion: Subjects of this study had the ability to comprehend and express wh-words. Comprehension of wh-words is easy for 4-6 year-old children they are able to use them in questions, but have some application errors.