• first language attrition;
  • second language acquisition;
  • age differences;
  • critical period hypothesis;
  • maturational constraints

The aim of the article is to examine how first language attrition research on maturational constraints interprets and links its findings to current views on maturation in the field of second language acquisition. It is argued that attrition research exhibits certain inconsistencies in the interpretation of the structural characteristics of the critical period and the interplay between maturation and nonmaturational factors in attrition. In view of findings from first language relearning/reactivation and theoretical-methodological advances in second language research on maturation, the article proposes a reinterpretation of maturational constraints in language attrition that, first, emphasizes the gradual decline of susceptibility to attrition and, second, puts forth the conditioning function that the maturational constraints have on nonmaturational factors.