This article challenges a recent proposal for the theoretical interpretation of L1 and L2 interaction that results from the abrupt change of language environment in internationally adopted children. According to this proposal (Pallier, Dehaene, Poline, LeBihan, Argenti, Depoux and Mehler, 2003; Ventureyra, Pallier and Yoo, 2004), such children experience a total loss of their L1, while, as adults, they exhibit a nativelike ultimate attainment of their L2. These authors suggest that what they see as a total loss of L1 allows a resetting of the neural network that normally subserves L1 retention and hence permits a complete acquisition of the L2. Data from two of our own research projects, one on L1 remnants in Korean adoptees in Sweden, and the other on age of acquisition and ultimate L2 attainment of Swedish, which included data from Latin American adoptees in Sweden among other participants, suggest (i) that L1 remnants are indeed maintained, (ii) that L2 attainment is "not" enhanced by severe L1 attrition, and (iii) that there is an age dimension to both the degree of L1 attrition and the level of L2 ultimate attainment in international adoptees. We therefore contend that a maturational interpretation of language replacement data is preferable.