Many children learn language in a linguistically diverse environment where multiple languages or dialects are heard, each one having different rules for combining words to form sentences. How do children learn the rules of one language or dialect when other heard languages or dialects lack those rules and thus frequently violate them? A new study by Dr. Kalim Gonzales and his collaborators at the University of Arizona, DrsLouAnnGerken and Rebecca Gomez, reveals that learning dialect-specific rules might be easier when the dialects are heard at different times.

In the study, 12-month-olds listened to an artificial language consisting of two speech streams representing different dialects of the language, a "pure stream" with rules such as aXbY and a "mixed stream" completely lacking those rules (aXbY and aYbX sentences were both possible). Infants listened to the language over loudspeakers while playing quietly in a playroom. They were then tested for their ability to distinguish sentences following the pure stream's rules from sentences violating those rules.

The authors found that infants recognized the pure stream's rules only when the two streams alternated in minutes-long intervals, simulating when two dialects are heard in different communication contexts. Infants failed to learn the pure stream's rules when sentences from the two streams were randomly interleaved, simulating when two speakers of different dialects engage in a dialogue.

The authors speculate that hearing two languages or dialects at different times may be helpful for teasing them apart because infants lack the capacity to combine language input in memory over extended time periods. In other words, memory limitations in early life might actually facilitate language learning. Scholars such as Elissa Newport have entertained this "less-is-more" hypothesis for quite some time as one explanation for why children are expert language learners, but the hypothesis has not been previously considered with respect to the challenge of negotiating linguistically diverse input.

The research is to be published this summer in the journal Cognition.

Link to access the full paper:

Does hearing two dialects at different times help infants learn dialect-specific rules?