Do learners’ word order preferences reflect hierarchical language structure?

Previous research has argued that learners infer word order patterns when learning a new language based on knowledge about underlying structure, rather than linear order (Culbertson &Adger, 2014). Specifically, learners prefer typologically common noun phrase word order patterns that transparently reflect how elements like nouns, adjectives, numerals, and demonstratives combine hierarchically. We test whether this result still holds after removing a potentially confounding strategy present in the original study design. We find that when learners are taught a naturalistic “foreign” language, a clear preference for noun phrase word order is replicated but for a subset of modifier types originally tested. Specifically, participants preferred noun phrases with the order N-Adj-Dem (as in “mugred this”) over the order N-Dem-Adj (as in “mug this red”).However, they showed no preference between orders N-AdjNum (as in “mugs red two”) and N-Num-Adj (as in “mugs two red”). We interpret this sensitivity as potentially reflecting a asymmetry among modifier types in the underlying hierarchical structure