Predictability of meaning in grammatical encoding: Optional plural marking

The markedness principle plays a central role in linguistic theory: marked grammatical categories (like plural) tend to receive more linguistic encoding (e.g., morphological marking), while unmarked categories (like singular) tend to receive less linguistic encoding. What precisely makes a grammatical category or meaning marked, however, remains unclear. One prominent proposal attributes markedness to the frequency or predictability of meanings: infrequent or less predictable meanings are more likely to receive extra linguistic encoding than frequent or more predictable meanings. Existing support for the predictability account is limited to correlational evidence, leaving open whether meaning predictability can cause markedness patterns. We present two miniature language learning experiments that directly assess effects of predictability on morphological plural marking. We find that learners preferentially produce plural marking on nouns that are less probable to occur with plural meaning-despite the fact that no such pattern was present in learners' input. This suggests that meaning predictability can cause the markedness patterns like those that are cross-linguistically observed.