Past tense in L2 acquisition

[Steven Pinker]

In addition to Michael Ullman's study, David Birdsong and Jim Flege have
investigated the question:

Birdsong, D. & Flege, J. E. (2001) Regular-irregular dissociations in the
acquisition of English as a second language. In BUCLD 25: Proceedings of the
25th Annual Boston University Conference on Language Development (pp.
123-132). Boston, MA: Cascadilla Press.