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Late Talkers (LTs) are defined by small expressive vocabularies (Desmarias et al., 2008) but vary in whether their receptive vocabularies are also impaired. We focus on receptive verb vocabulary, as verb knowledge better predicts grammatical outcomes than noun knowledge (Hadley, Rispoli, & Hsu, 2016). Fernald and Marchman (2012) found that LTs know fewer nouns and are slower to identify the correct visual referent from two choices than are age-matched peers (TDs). We hypothesize the same is true of verbs, applying an eye-tracking paradigm for assessing receptive verb vocabulary (Valleau et al., under revision). Two-year olds (N = 33) viewed two dynamic scenes and were asked to find which depicted the target verb; eye gaze was recorded. A regression revealed that TDs knew more verbs than LTs. Although LTs trended toward slower speeds, our regression yielded no significant group differences. Group differences in receptive verb knowledge may explain why LTs have long-term poorer outcomes (e.g., Rescorla, 2005), and may ultimately help predict which are most at risk for language disorder. Funding: NIH K01 DC013306 and ASHFoundation New Century Scholars Research Grant. |
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