Abstract
In this chapter, we present the Modular Cognition Framework (MCF), formerly known as the Modular Online Growth and Use of Language (MOGUL) framework. In particular, we describe how the MCF can be applied in order to explain the mechanisms that drive the acquisition of a second language (Sharwood Smith, 2017; Sharwood Smith & Truscott, 2014a; 2014b; Truscott & Sharwood Smith, 2019a).