Speech after adoption: Relearning to perceive birth language contrasts by international adoptees
Children who are adopted into a country where another language is spoken commonly stop using their birth language abruptly soon after adoption. Within only a few years or even months, they do not seem to remember anything about their birth language, even if they spoke and understood it well at the time of adoption. This is remarkable, given the special status of the first language, which is very robust and usually not forgotten even after many decades of disuse. In this talk I will present the results of two studies that used phonetic retraining of birth language contrasts to investigate whether international adoptees truly forget their birth language, or whether traces of the ‘forgotten’ birth language, in particular its phonology, remain and can be retrieved with re-exposure.
Study 1 investigates birth language attrition in progress, assessing Mandarin and Cantonese Chinese children in the Netherlands, who had been recently adopted, between six months and nine years prior to testing. Adopted children and a control group of Dutch children with no prior experience with Chinese were trained and tested on perception of Chinese affricate and tone contrasts which were difficult to distinguish for native Dutch listeners. Results show that even for these very recently adopted children, the birth language was not immediately accessible anymore. Re-exposure, however, led to a relatively fast improvement of perception of the birth language sounds, such that adoptees soon outperformed the Dutch control participants.
Study 2 addresses birth language memories several decades after adoption. It investigates whether Korean adoptees in the Netherlands still remember part of their birth language phonology by the time they reach adulthood. Korean adoptees and Dutch control participants were trained and tested on perception of Korean lenis/fortis/aspirated contrasts which are difficult to distinguish for Dutch listeners. Results show that initially (i.e., at the pretest), the Korean adoptees did not perceive the Korean phonemes better than the Dutch control participants. After several training sessions, however, the Korean adoptees did outperform the control group.
Both studies thus provide evidence that international adoptees do retain memories of their birth language phonology and that this aids them in relearning the sounds later in life.