Behavioural evidence suggests that English regular past tense forms are automatically decomposed into their stem and affix
(played = play+ed) based on an implicit linguistic rule, which does not apply to the idiosyncratically formed irregular forms
(kept). Additionally, regular, but not irregular inflections, are thought to be processed through the procedural memory
system (left inferior frontal gyrus, basal ganglia, cerebellum). It has been suggested that this distinction does not to apply to
second language (L2) learners of English; however, this has not been tested at the brain level. This fMRI study used a
masked-priming task with regular and irregular prime-target pairs (played-play/kept-keep) to investigate morphological
processing in native and highly proficient late L2 English speakers. No between-groups differences were revealed.
Compared to irregular pairs, regular pairs activated the pars opercularis, bilateral caudate nucleus and the right cerebellum,
which are part of the procedural memory network and have been connected with the processing of morphologically
complex forms. Our study is the first to provide evidence for native-like involvement of the procedural memory system in
processing of regular past tense by late L2 learners of Englis