Attempts to provide representational accounts of second language (L2) optionality are
always welcome because they provide us with tools to determine whether and to what
extent non-native grammars are idiosyncratic. In their keynote article, Amaral and
Roeper (this issue; henceforth A&R) have also devised a specific way of accounting for
how an L2 (or an L3 or an Ln grammar) is added to the initial first language (L1) representation.
However, we are left with the need to determine more specifically what is
actually added; whether the end result is a grammar with the same features (or parametric
properties) as the input L2 grammar, as well as what the predictive power of the model
may be. In this commentary, I will refer to previous L2 research dealing with optionality
in order to