Pack of 20 Examiner Record Booklets for the SLDT-E: NU. The Social Language Development Test–Elementary: Normative Update (SLDT-E: NU) assesses language-based skills of social interpretation and interaction with friends (the skills most predictive of social language development). Specifically, it measures the language required to appropriately infer and express what another person is thinking or feeling within a social context, to make multiple interpretations, take mutual perspectives, and negotiate with and support their peers. These tasks reflect the developmental refinement of social language comprehension and expression and differentiate typically developing children from those with autism spectrum disorder.