Table 2. Research questions (RQs).

(RQ)	RQ statement	Objectives and motivation
RQ1:	What were the high-quality publication channels for MALL research, and which geographical areas have been targeting MALL research over the years?	The objectives of RQ1 were to search for high-quality research articles through major publications channels for MALL research. Furthermore, the quality assessment for the selected articles and the meta-information extracted useful statistics, including the geographical areas and publication, trended over the years.
RQ2:	What were the widely used theories, models, and frameworks proposed or adopted for MALL research?	To identify the theories and frameworks/conceptual models used for MALL research and related them to different application areas for MALL.
RQ3:	What were different application domains for the MALL application, and in which various forms were these applications exposed for the end-users?	To identify different target application areas of MALL from teaching and learning perspectives. Furthermore, identify different modes of exposition for these MALL applications.
RQ4:	What was the specific content adopted for teaching and learning in MALL research?	To accommodate different contents for MALL applications focusing on reading, writing, speaking, and listening perspectives.
RQ5:	How and in what different perspectives the MALL applications were evaluated, and what were the evaluation measures and tools used for their evaluation?	Outline the standard process, tools, and instruments used for the evaluation of MALL applications. Furthermore, identify the evaluation measures for MALL applications concerning different perspectives, including teaching and learning and technical perspectives.
RQ6:	Compare the usage of simple mobile applications with gamified applications (Serious Game) for language learning?	To perform a comparative analysis to evaluate the effectiveness of simple mobile application-based language learning with gamified mobile applications for language learning.