What is a word : understanding developmental changes in the sounds infants accept as possible labels

• Main Author: May, Lillian Anne
• Language: English
• Published: University of British Columbia 2010
• Online Access: http://hdl.handle.net/2429/27483

Language is a conventional system: the use of words is shared within a language community. Even further, each language community has conventions regarding what “forms” may serve as words. A form (the phonological sounds or hand movements that make up a word) used in one community may not be proper in another. It is therefore important that when young language learners acquire a language, they adhere to both the general conventionality of language and the word-form conventions of their particular language(s). Previous research has demonstrated a developmental narrowing in the word-forms that infants are willing to accept as conventional labels. Younger word-learning infants view a wider range of symbols as potential labels than do older infants. The present study takes this research further, and specifies the nature of this developmental narrowing. Two potential word-learning constraints are explored: a Linguistic word-learning constraint, in which infants limit the symbols they view as potential labels according to whether the label-form consists of components that occur in at least one of the world’s languages, versus a more restrictive Native Language Assimilation constraint, in which infants limit symbols according to whether the components within the label-forms assimilate into native language speech categories. In addition, this research probed whether the development of such constraints is related to infants’ vocabulary acquisition. In the present study, I explored infants’ ability to learn unassimilable yet linguistic click words as object labels. In Experiment 1, I first established the effectiveness of the novel two-object Referential Switch paradigm, demonstrating that 14-month-old infants succeed in learning unassimilable click words as object labels in this task. In Experiment 2, I then tested 20-month-old infants to investigate the development of a Linguistic versus Native Language Assimilation. I found that while 20-month-old infants with smaller vocabularies were able to learn the unassimilable click words as labels, infants with larger vocabularies were not. These results suggest that the narrowing that occurs between 14 and 20 months of age in infants’ awareness of word-form conventions is best explained by the development of a Native Language Assimilation word-learning constraint.