Development of Past Tense Counterfactual Sentences: Examining Production and Comprehension in Adolescents and Adults.

Purpose The primary purpose of this study was to examine the development of past tense counterfactual (PTCF) sentences ("If the dog had stayed in the house, he would not have bitten the police officer") in young adolescents and young adults, addressing both production and comprehension. The goal was to determine if growth occurs during the years between early adolescence and early adulthood and when or if mastery of these sentences occurs. We also examined the development of past tense irregular verbs to determine growth and mastery. Method The participants included one group of young adolescents ( = 12.44 years, = 80) and one group of young adults ( = 21.30 years, = 80). All were monolingual speakers of Mainstream American English. Using a written language task, each participant completed a set of 40 sentences. For each sentence, the missing element affected the main clause (present perfect verb omitted), the subordinate clause (past perfect verb omitted), or either the main or the subordinate clause (past tense irregular verb omitted). To examine differences in production versus comprehension, half the participants in each group used a fill-in response format (production task), and half used a multiple-choice response format (comprehension task). Results On the PTCF sentences, the adults outperformed the adolescents, comprehension exceeded production, both groups experienced greater difficulty with the past perfect compared to the present perfect verb form, and the adults were more likely to show mastery of PTCF sentences than were the adolescents. Similarly, on the past irregular verbs, the adults outperformed the adolescents, and the adults were more likely to show mastery of these verbs. Implications The findings of this study contribute to the knowledge base in later syntactic development and suggest that some adolescents and adults may require formal instruction in subtle aspects of English grammar used in literate contexts, such as PTCF sentences. Supplemental Material https://doi.org/10.23641/asha.11971872.