A number of SLA studies in the past decade (e.g. Lardiere, 1995; Murphy, 2000) have attempted to answer the question of whether the Dual-Mechanism Model can be extended to L2 English processing. These studies have found that the clear regular-irregular dissociation in compounds observed for L1 users is not the case for L2 users, who tend to include regular plurals in compounds to varying degrees. The present study reports on further efforts to investigate this issue with Turkish learners of English as a Foreign Language (EFL) in Turkey. An elicited written production task, similar to that used by Murphy (2000), was administered to high and low proficiency L1 Turkish users of EFL and native English speakers. The results, it is claimed, indicate that both the L1 controls and the L2 participants dissociate between regular and irregular nouns within English compounds. However, in contrast to most previous studies, the L2 dissociation was found to be stronger at higher levels of L2 proficiency, which speaks for a developmental restructuring in L2 inflectional processing that could be explained under a weak version of the Dual-Mechanism Model.