Die Muttersprache vergisst man nicht - or do you? A case study in L1 attrition and its (partial) reversal

Is it possible to undo or reverse language attrition? In other words, has there been, in the case of attrition, a permanent change with respect to the speaker's L1 knowledge, or do we only see temporary effects on the control of that knowledge? It is proposed here that the concept of attrition should include the temporary loss of language skills since it is, so far, not clear whether or to what extent once-acquired linguistic abilities can be permanently lost at all, particularly with respect to an L1. A reversal in the development of attrition after renewed contact with the L1 can support the claim that a decrease in L1 proficiency can be TEMPORARY, and that it is the ACCESSIBILITY of items and structures that is affected by attrition rather than the L1 knowledge (competence) itself. Our primary research interest in the present study is to analyze what skills and features are recoverable and what phenomena persist, (possibly) indicating permanent loss.