In this commentary to Westergaard (2021), we focus on two main questions. The first, and most important, is what type of L3 data may be construed as supporting evidence--as opposed to a compatible outcome--for the Linguistic Proximity Model. In this regard, we highlight a number of areas in which it remains difficult to derive testable predictions…

The present systematic review examines what factors determine when, how and to what extent previous linguistic experience (from the first language, second language or both languages) affects the initial stages and beyond of adult third language (L3) acquisition. In doing so, we address what a bird's eye view of the data tells us regarding…