Recent studies have come to contradicting conclusions as to whether international adoptees, who experience a sudden change in language environment, lose or retain traces of their birth language (Pallier et al., 2003; Ventureyra, Pallier & Yoo, 2004; Pierce, Klein, Chen, Delcenserie, & Genesee, 2014). Though these studies have considered cortical differences between international adoptees and individuals from their birth counties, none has looked at subcortical differences in the brain between the two groups. The current project examined the frequency following response of adult Chinese international adoptees (N = 9) adopted as infants by American English-speaking families in the United States compared to native Mandarin (N = 21) and American English (N = 21) controls. Additional behavioral tasks were completed to explore different levels of linguistic features from phonetics to phonology to semantic knowledge to suprasegmental characteristics of speech. The FFR results indicate mostly good pitch tracking abilities amongst the adoptees that may support future tonal language learning in the adoptees. The behavioral data suggest that the adoptees have minimal access to all levels of linguistic levels of linguistic processing (i.e., phonetic, phonological, lexical, suprasegmental) after adoption and after early exposure to English. Overall, the data provide evidence for the neural commitment theory that humans’ language acquisition is attuned to their language environment early on in life
