This paper explores whether the poor mastery of morphosyntax exhibited by second language (L2) learners can be tied to difficulties with non-syntactic processing. Specifically, we examine whether problems with English regular and irregular past tense are related to poor L2 phonological ability and lexical access, respectively. In Experiment 1, L2 learners showed poorer past tense mastery than native English speakers in grammaticality judgment and production tasks. L2 phonological ability was positively correlated with correct performance on regular verbs and negatively with unmarked production. L2 lexical access was positively correlated with correct performance on irregular verbs, and negatively with overregularization production. Experiment 2 simulated these difficulties in native English speakers by placing them under phonological processing (noise) or lexical access (deadline) stress. Noise selectively impacted regular verbs in grammaticality judgment but impacted all verb types in production. Deadline pressure impacted irregular verbs while sparing regular verbs across both tasks. Thus, non-syntactic processing difficulties can have specific impacts on morphosyntactic performance in both non-native and native English speakers.
(Received April 09 2009)
(Revised December 09 2009)
(Accepted December 17 2009)
(Online publication March 15 2010)
* A preliminary version of the data reported in this paper was presented at the 47th annual meeting of the Psychonomic Society, Houston, TX. We thank Matthew Calamia, Patrick Johnson, Alina Oster, Michael Rhea, and Erin Thomas for help in gathering the data.