This volume presents a range of studies testing some of the latest models and hypotheses in the field of second/third language acquisition, such as the Bottleneck Hypothesis (Slabakova, 2008, 2016), the Scalpel Model (Slabakova, 2017), and the Interface Hypothesis (Sorace & Serratrice, 2009) to name a few. The studies explore a variety of linguistic properties (e.g., functional morphology, linguistic properties at the syntax-discourse interface) by focusing on distinct populations (L2 acquisition, L3/LN acquisition, Heritage Speakers), while also considering the links between experimental...