Effects of Short-Term Exposure to Spanish on the Babbling of English-Learning Infants
Nancy Ward - nancyward@ucla.edu
Megha Sundara - megha.sundara@humnet.ucla.edu
University of
California, Los Angeles
3125 Campbell Hall Box 951543
Los Angeles, CA 90095-1543
Barbara Conboy
Institute
for Learning & Brain Sciences
University of Washington
Seattle
Department of Communicative Disorders
University of Redlands
Patricia K. Kuhl
Institute
for Learning & Brain Sciences
University of Washington
Seattle
Popular version of paper 5aSC2
Presented Friday morning on Friday, October 30, 2009
158th ASA Meeting, San Antonio, TX
Second language learning has been acknowledged in linguistic research as easier for children then adults. But exactly how much easier is second language-learning for children? Can just a few weeks of limited exposure alter an infant's language abilities? Previous research has shown that even short-term exposure is enough to affect an infant's ability to process the sounds of a second language. However, researchers know little about whether exposure to a second language can also influence the production of sounds. Can this limited, short-term exposure also influence the way that an infant babbles?
Children start to develop their native language listening skills between 0 and 12-months of age. During this time, childrens ability to distinguish sounds in a foreign language declines, whereas their ability to distinguish sounds in their native language improves. For example, Japanese as well as English-learning 6-8-month-olds are able to distinguish English /r/ and /l/. However, by 10-12-months, Japanese-learning infants, like Japanese adults, have difficulty distinguishing English /r/ and /l/. In contrast, English-learning 10-12-month-olds get better at distinguishing English /r/ and /l/. This perceptual tuning into the native language has been well documented.
Far less is known about a child's production at this point in life. When does an infants babbling become tuned into her native language? Can this change in the infants babbling be initiated with short-term language exposure within the first year of life?
Our study looks at whether infants from monolingual English-speaking households will alter their babbling after short-term exposure to Spanish. We selected 13 infants between 9 and 10-months of age from English-speaking homes. These infants were exposed to Spanish in 30-minute sessions, twice a week, spread out over 6 weeks for a total of about 5 hours. During the exposure sessions, Spanish-speaking research assistants played and read stories to the infants. After this exposure, the infants -- now 12 months olds -- participated in two different "babbling" sessions in which everything they said in a half hour play session was recorded. One of the babbling sessions was with an English-speaking parent and the other was with a Spanish-speaking research assistant. The goal of these babbling sessions was to elicit speech from the infants in each of the two language settings. The purpose of this study is to determine whether the infants babbling in the Spanish and English settings were different.
Spanish and English differ in their linguistic characteristics in a number of ways. First, Spanish and English differ in the consonants and vowels that are used to denote meaning. For example, there is a clear difference in how the 'r' in produced in English (as in "carrot") and Spanish (the trill in "perro" or dog); further, Spanish words do not have the vowel in "cat". Second, Spanish and English also differ in their rhythmic properties, such as the length of words and their stress patterns. About 80 percent of words in conversational English are only one syllable long (as in "cat", "ball", and "dog"). This is not the case in Spanish; Spanish infants hear many words that are at least two syllables long (as in "gato" cat or "jugo" juice). Further, in conversational English, about 80 percent of words begin with a stressed syllable (as in "doctor" or "baby"); Spanish words have a much more variable stress pattern (as in "jvenes" young ones, "pelta" ball, and "espal" Spanish). Previous research indicates that by about 12 months, monolingual infants babbling shows some rhythmic as well as speech sound qualities of their native language.
We are beginning our study with a listening experiment. This is designed to determine whether adult native speakers of Spanish and English can hear any differences in the babbling of infants recorded in the Spanish or English-session. This difference can be at the level of consonant and vowels or even at the rhythmic level. If adult native listeners of Spanish and English can hear the differences in the babbling, we will know that there short-term exposure can alter babbling. If the adult listeners are not able to hear any differences, we will follow-up with a quantitative acoustic analysis of the babbling. This analysis may show differences that are just too minor to perceive. Our results will have implications for the impact of language exposure on acquisition.