Past tense and past participle verb use in young children with and without Specific Language Impairment

Abstract

Finiteness marking is an area of weakness in specific language impairment (SLI) and two hypotheses attempt to account for this difficulty. The Extended Optional Infinitive (EOI) account proposes that SLI children have difficulties with the morphosyntactic properties of verbs. The surface account proposes that SLI children have difficulties with the surface properties of morphophonology. In English, the regular past participle provides an interesting test case for these hypotheses - it is not marked for finiteness, yet is homophonous with the regular past tense. Thus, children's use of regular past participles offers a window to explore further the source of the weakness in regular past tense marking. Previous studies yield inconclusive outcomes for regular forms and do not explicitly compare irregular forms. This study aimed to address the inconsistency in the literature by comparing regular past tense and regular past participle accuracy longitudinally, and explicitly comparing irregular past tense and irregular past participle accuracy. Participants included 65 SLI children (M = 5;5), 59 age-equivalent (AE) controls (M = 5;6), and 32 language-equivalent (LE) controls (M = 3;3). Two spontaneous language samples were collected approximately one year apart. At Time 1, SLI children were less accurate on the regular past participle than both AE and LE controls, but did not differ at Time 2. At Times 1 and 2, SLI children did not differ from AE controls on the irregular past participle. At Time 1, SLI children were more accurate on the regular past participle than the regular past tense, but did not differ at Time 2. Contrastingly, SLI children were more accurate on the irregular past participle than the irregular past tense at Times 1 and 2. As predicted by the EOI account, the past tense is more difficult than the past participle for SLI children irrespective of form. For SLI children, the past participle is easier than the past tense, with the irregular past participle conferring a greater advantage than the regular past participle. In general, the results are consistent with previous reports on homophonous forms and highlight the importance of age at time of assessment when evaluating group differences.