Languages are subject to many competing pressures, whichoriginate in individual-level learning and communication bi-ases and in social biases reflecting community-level dynamics.Recent work suggests that certain aspects of language struc-ture, such as the cross-linguistic trade-off between case andconstituent-order flexibility, originate in learners’ biases forefficient communication: Learners drop redundant case but re-tain informative case in production. Social biases can lead toretention of redundant case, resulting in systems that requiremore effort to produce. It is not clear, however, whether socialbiases can influence the use of informative cues. We tested thisby exposing participants to a language with uninformative con-stituent order and two dialects, only one of which employedcase. We manipulated the presence of social biases for andagainst the case dialect. Learners biased towards the no-casedialect dropped informative case without compensating for theresulting message uncertainty. Case was retained in all otherconditions.

Miniature language learning is gaining increasing popularity to study biases underlying language universals. However, it is unclear whether learning preferences in these studies are influenced by learners’ native language. We ask whether a previously identified bias to balance production effort against message uncertainty holds across speakers of structurally different languages. We expose English (fixed order language without case) and German (flexible order language with case) speakers to miniature languages with optional case and either fixed or flexible constituent order and study their deviations from the input. We find that English and German speakers restructure the input in the same way: They match the input constituent order proportions and use more case in the flexible order language than in the fixed order language, thus following the bias to balance production effort against message uncertainty. Our findings suggest that this bias and its specific realization are independent of learners’ native language.