An article by Acrisio Pires, in collaboration with Jason Rothman, has been included in the 20th-Anniversary Virtual Special Issue of the International Journal of Bilingualism. This anniversy issue brings together the 20 most cited papers over the 20 year history of the journal. Congratulations, Acrisio, on this well-deserved recognition! The whole volume has been made available for free by the publisher at this link. We include the bibliographic information of the original Pires & Rothman paper below, together with an abstract.

Pires, Acrisio, and Jason Rothman. 2009. Disentangling sources of incomplete acquisition: An Explanation for competence divergence across heritage grammars. International Journal of Bilingualism 13(2):211-39.

The article brings to light an important variable involved in explaining a type of competence divergence in an instance of bilingual acquisition: heritage speaker (HS) bilingualism. It present results of experiments with European Portuguese (EP) heritage speakers (HSs), showing that they have full morpho-syntactic and semantic competence of inflected infinitives, similar to EP monolinguals. The article presents evidence that neither incomplete acquisition nor attrition hinders the acquisition of inflected infinitives by European Portuguese HSs, raising questions regarding how to explain the competence divergence between HSs of the two dialects. The paper argues for a more fine-grained approach to incomplete acquisition, proposing a type of missing-input competence divergence by which insufficiency of input from a standard dialect can affect acquisition, and heritage speakers of different dialects can show systematic mismatches in their adult knowledge if syntactic changes differentially affect the properties of the colloquial dialects to which these speakers are exposed.