What’s so incomplete about incomplete acquisition?

Modeling the competence grammar of heritage speakers who exhibit low proficiency in their L1 represents a significant challenge for generative and experimental approaches to bilingual linguistic research. In this paper we revisit the core tenets of the incomplete acquisition hypothesis as developed in recent scholarship (in particular by Montrul (2002 et seq.) and Polinsky (1997 , 2006 )). Although we adopt many of these fundamental aspects of this research program, in this article we develop an alternative model that provides a more accurate depiction of the process that leads to what these scholars describe as the (later) effects of incomplete acquisition, thus improving the predictive power of this research program.