A Calvin College professor of Spanish has earned a grant from the National Science Foundation (NSF) to study language acquisition in Chile and Mexico City. 
“The ability to acquire language is innate and specific to humans, and we know that the language children acquire is based on the language that they hear around them,” said Karen Miller, a Calvin professor of Spanish, who will use the three-year $166, 217 NSF grant to study how children native to those two places learn and incorporate plural morphology in Spanish. “What I am interested in is how different types of variation in the language children hear affects the type of language they initially acquire,” 
Miller’s specific focus is the plural marker, which in Spanish, as in English, is the "s” sound. Yet while children in Mexico City regularly hear their parents using the “s” to make one perro (dog) into two perros (dogs), children in Chile hear their parents adding the “s” with less constancy; instead, it is sometimes produced by adults and sometimes omitted in plural noun phrases.
“How will the input that Chilean children hear affect the language that they acquire?” Miller expressed her basic research quandary. “Will they build a language system with plural morphology (like English) or one without plural morphology (like Chinese)? While focusing on the acquisition of plural morphology may seem very small, she said, it is important because it teaches us how the human brain organizes different types of linguistic input in the acquisition of language: “We are finding that children who receive inconsistent input take longer to acquire morphology when compared to children who receive consistent input.”
Miller will collect nine hours of conversation between 64 parent-child pairs in both Chile and Mexico City and compare them for use of the plural marker. In addition, all child participants will be tested for comprehension of the plural marker in nine different experimental tasks. The goal is to correlate the absence of plural morphology in the children’s input to their performance on comprehension tasks.
Calvin student researchers will be essential to her work, Miller said. One group of researchers will transcribe the conversations; another group will provide phonetic transcription of the plural marker; and a third will make a morphological transcription and carry out statistics on the data. “Looking at this very small thing means hours and hours of work,” she said.
Though the research has a seemingly specific focus, it may shed light on the wider picture of how languages change. “We know that language change occurs as children construct a language that is slightly different than their parents’ language. In Chile, we might predict that over time plural morphology may be lost. There has been some evidence that in other dialects of Spanish with ‘s’ lenition, the plural marker is no longer associated to 'more than one,'” Miller said. 
This project also has practical implications for language testing and standardized tests in education. “It has been reported that difficulty with plural morphology may be a way to diagnose language disorders in Spanish-speaking children. These tests would not be appropriate for children learning varieties of Spanish with ‘s’ lenition,” she said. “This work then will provide valuable information for language specialists in order to create dialect-sensitive tests for Spanish children.”
Miller’s and the students’ three years of research will be published in journals related to linguistics and cognitive science and presented at several conferences. It will also be posted on the CHILDES database, a digital collection of transcript and media data collected from conversations between young children and their playmates and caretakers.
"That way, other researchers from anywhere in the world can use our data,” Miller said.