Tense Over Time

TLDR

Tense marking in English emerges late, especially in children with Specific Language Impairment, and its acquisition trajectory remains poorly understood despite its central role in morphosyntax and language development. The study followed 43 typically developing and 21 SLI children longitudinally from ages 2.6 to 8.9 and 4.6 to 8.8, respectively, to track tense‑marking acquisition. Results show that tense‑marking morphemes are acquired only after age 4 in typical children and after age 7 in SLI children, following an S‑shaped curve, with initial mean length of utterance predicting acquisition rate but nonsyntactic measures not; these patterns support Optional Infinitive and Extended Optional Infinitive models.

Abstract

Tense marking in English is relatively late appearing and is especially late for children with Specific Language Impairment (SLI). Little is known about the full course of acquisition for this set of morphemes. Because tense marking is a fundamental property of clause construction, it is central to current theories of morphosyntax and language acquisition. A longitudinal study is reported that encompasses the years of 2;6–8;9 years for typically developing children ( N =43) and 4;6–8;8 years for children with SLI ( N =21). The findings show that a diverse set of morphemes share the property of tense marking; that this set is not mastered until age 4 years in typically developing children and after 7 years for children with SLI; that acquisition shows linear and nonlinear components for both groups, in a typical S-shaped curve; and that nonsyntactic measures are not predictors of growth (including nonverbal intelligence, vocabulary size, and mother’s education), whereas initial MLU does predict rate of acquisition. The findings are consistent with a model of Optional Infinitives (OI) for typically developing children (cf. Wexler, 1994, 1996) and Extended Optional Infinitives (EOI) for children with SLI. This model hypothesizes incomplete specification of features of tense that are represented in the grammar.