Retention of Speech Sound Production and Perception in Young International Adoptees

While international adoptees commonly report not remembering their birth language, studies have shown that with re-exposure they learn to perceive birth-language sounds faster (Choi et al., PNAS, 2017; Pierce et al., PNAS, 2014, Singh et al., DevSci, 2011) and to pronounce them more accurately (Choi et al., RSOS, 2017) than non-adopted controls. We assessed birth-language memories in much younger adoptees than tested before, investigating whether memories were episodic or abstract in nature and which process—imitation or perception—survived longest. Participants were (Experiment 1) 21 Cantonese and (Experiment 2) 25 Mandarin adoptees in the Netherlands and 47 Dutch control children, aged 4-11. They were trained on perception of Cantonese/Mandarin affricate and tone contrasts, and tested on perception and production (imitation; recordings assessed by native-speaker identification and rating). For perception, adoptees initially performed similar to controls but outperformed them after training, similar to findings for adoptees tested as adults. For production, however, adoptees already outperformed controls from the pre-test, in contrast to previous results for adult adoptees. Thus, while international adoptees retain abstract memories of their birth language phonology which helps them in relearning the sounds later in life, imitation ability stands the test of time better than perception ability.