Individual variation in Swedish and American 12- and 18-monthers' babbling as judged by expert listeners
Proceedings of the XIIIth Swedish Phonetics Conference (FONETIK 2000) Skövde, Sweden, May 24-26, 2000: 57-60.
There is lack of agreement on the extent to which infants' vocalizations are influenced by the sounds of the ambient language. In this experiment, 5 expert listeners were asked to discern ambient language effects on babbled vocalizations produced by American and Swedish 12- and 18-month-olds. Listener responses revealed considerable individual variability among children in both age groups; whereas about half of the 18-monthers were correctly recognized with respect to ambient language, most - but not all - 12-monthers produced vocalizations that were not sufficiently native-sounding to be reliably identified. Some children's vocalizations thus displayed recognizable effects of ambient language as early as 12 months of age, whereas other children failed to display such effects at 18 months. Even though negative listener responses do not necessarily indicate a complete absence of an ambient language influence on babbling, the results suggest that theories advocating either an early or a late onset may be overly categorical. The question would probably turn out to be less controversial if sufficient attention were paid to individual development patterns underlying the group data.