How endpoint salience and semantic distance shape L2 implicature derivation behavior in gradable adjective scales

Abstract

Research on scalar implicatures has increasingly highlighted ‘scalar diversity’, showing that pragmatic inferences vary systematically across lexical scales rather than arising uniformly. Two factors pertaining to the semantic structure of adjectives are found to play a particularly influential role: ‘endpoint salience’, where scales with fixed boundaries more readily support implicatures, and ‘semantic distance’, where the further a stronger scalemate is from its weaker counterpart, the more likely an implicature is to be derived. While these effects are well documented among native speakers, little is known about how second language (L2) learners navigate such dimensions. Across three experiments, we examined how proficiency modulates L2 learners’ sensitivity to these semantic factors in gradable adjectives. Experiment 1 showed that learners were broadly sensitive to whether or not an adjective denotes an endpoint, but awareness strengthened as proficiency increased. Experiment 2 revealed that learners’ perceptions of semantic distance between scalemates were more pronounced on scales with endpoint denoting adjectives versus those without. Experiment 3, an inference evaluation task, demonstrated that while both groups generated more implicatures on bounded than unbounded scales, lower proficiency learners tended to endorse implicatures more broadly, whereas higher proficiency learners displayed a near native-like tendency to suspend inferences until sufficient context was available. Together, these findings suggest that increasing proficiency promotes greater sensitivity to scale structure and more flexible integration of semantic and pragmatic information during implicature generation.