Research in my lab seeks to understand how language production and comprehension are shaped by the competing pressures inherent to communication, and how this in turn affects the development of language over generations. The talk is divided into two parts. The first part presents a quick overview of some of our research on language production. This work investigates whether the systems underlying language production are organized so as to balance the demands inherent to production (e.g., sequential planning) and the goal of efficient information transfer (i.e, fast and robust inference of the intended message, incl., but not limited to, propositional, pragmatic, and social information). Specifically, I'll focus on sentence recall studies on optional case-marking in Japanese (Kurumada & Jaeger, 2013, under review). We find that Japanese speakers are more likely to mark grammatical object with case, if the meaning conveyed by the sentence is less expected (based on plausibility norms). If time permits, I'll present similar data from phonetic production, where speakers hyperarticulate VOT contrasts when the contextual confusability of the intended target word would otherwise have been high (Buz & Jaeger, 2014, in progress).

In the second part of the talk I present research on the acquisition of case-marking and how case-marking and other cues to sentence meaning (animacy, word order, etc.) trade-off during acquisition (Fedzechkina, Jaeger, Newport, 2012; Fedzechkina, Newport, Jaeger, under review; Blackley, Fedzechkina, Jaeger, in progress). We find that learners change the statistics of the input language they receive in a way that reduces the uncertainty (entropy) over intended meanings while holding production effort constant (or even lowering it). This suggests that at least some properties of languages across the world are a consequence of one of the most common goals of language use: the transfer of messages. These findings also provide a causal link for previously observed language change as well as well-documented typological patterns (e.g., the inverse relation between case-marking and configurationality).