The purpose of this study is to discuss the effects of audiovisual input on second language acquisition (SLA) and the factors that influence the difficulty of audiovisual learning through a systematic literature review. Prior to this systematic review, in this paper, we searched papers on related topics for the past 10 years from 2012 to 2022, and found 46 journal papers that met the research criteria. They can basically represent the scholarly work in this field. The 46 studies were published in journals indexed in Google Scholar, Eric, Scopus, and Wiley Library. Databases were selected according to a set of inclusion and exclusion criteria. The following conclusions are drawn from the literature review: Audiovisual input can provide more authentic language input and more adequate and richer multimodal cultural and situational contexts, which can better promote learners' understanding of the content and stimulate learners' interest in participating in listening comprehension tasks. The influencing factors of multimodal input on listening difficulty include subtitles, video type, and the relationship between the audio and visual input.

In recent years, there has been an interest in using visual input in multimodal applications for language learning. However, the effects of visual input in listening materials remain to be discussed. Past literature has shown no unified answer to the effects of video input in improving listening comprehension scores. Since there are many proposals for the diversified reform of English teaching methods, it is worth examining whether using traditional audio listening only or using different video inputs can bring more significant benefits to students. The subjects of this study are 30 non-English majors in Chinese universities. This paper applied the quantitative research method, testing students’ performance using different listening visual inputs (content, context, and audio only) and different listening text types (monologue and dialogue). Data were analysed using the two-way repeated measures within groups ANOVA. The interaction effects and the main effect of variables on listening performance were examined to explore the impact of visual input and text types on English listening comprehension. The following conclusions are drawn from the data analysis: (1) The interaction effect shows that video and text types significantly affect students’ listening scores. Videos that contain authentic listening scenes and content elements are beneficial to promote listening comprehension as they support students’ interpretation and understanding of what they hear, and (2) It was noted that grouping students by listening proficiency and examining their cultural background would expand the study in the future.