The second noteworthy point of verb tense performance is the intraindividual variability across tense types; that is, many PWAA's accuracy was widely different across tenses (e.g., JS scored 0.3 and 0.8 for past and present tense, [11]; see the Appendix).
These accounts propose that mapping of conceptual-semantic representations onto morphosyntax involved in tense marking is challenging for PWAA, primarily because it involves more computations and strictly structural operations such as verb agreement.
