Developmental Characteristics of Lexical, Syntactic, and Cohesive in Children’s and Adolescents’ Expository Writing

This study analyzed expository discourse writing samples from 51 studentsin the fourth and sixth grades of elementary school and the second grade of middle school. The purpose was to examine developmental trends of related factorsand to provide foundational data for the assessment and intervention of languageand literacy during this period. The research questions explored whether there weregrade-level differences in vocabulary, syntax, and cohesive markers in expositorytexts, and what correlations were observed among these factors. In the vocabularydomain, the total number of words (NTW) and the number of different words (NDW)were measured. Syntactic complexity was assessed using the mean length of T-unitin words (MLT-w) and clause density. For the cohesive marker domain, analysesincluded the total number of cohesive markers, the accuracy rate of cohesivemarker use, and the mean number of cohesive markers per T-unit. Multivariateanalyses and correlation analyses were conducted. Overall, results revealed aprogressive increase across grade levels in lexical diversity, syntactic complexity,and both the frequency and accuracy of cohesive marker use. These gains weremodest between Grades 4 and 6 but became markedly more increased by Grade 8. The findings underscore the importance of continued monitoring and support of notonly lexical and syntactic development but also the mastery of fine-grainedgrammatical devices that contribute to textual cohesion throughout adolescence.