A Linguistic Perspective on the Interplay of Grammar and Speaking Skills in Second Language Acquisition

This paper looks at how teaching grammar affects the development of speaking skills in second language acquisition (SLA). It uses empirical studies that were published between 2005 and 2025. Using the PRISMA 2020 framework, 50 high-quality peer-reviewed articles were examined based on strict inclusion criteria. Using the Complexity, Accuracy, and Fluency (CAF) framework, the paper sorts out the results and looks at the factors that affect grammar's effect on speaking, such as the way it is taught, the theory behind it, and the context in which it is used.

 The results show that teaching grammar is a reliable way to improve speaking accuracy, especially when the lessons are clear and focused on output. Task-based grammar instruction (TBGI) consistently makes sentences more complex, but it only makes people more fluent after they have practiced speaking and writing a lot. The study backs up the weak interface position, which says that speaking activities that focus on meaning can help people move from knowing grammar to using it without thinking about it. Other factors, like the learner's skill level, the way the task is set up, and the type of feedback, also affect how effective the instruction is.

 Interlanguage Theory, Skill Acquisition Theory, and Sociocultural Theory are the three theories that the study is based on. They all explain how grammar becomes procedural through speaking. Interlanguage Theory backs up the idea that grammar and speech depend on each other through input-output-feedback loops. Skill Acquisition Theory says that grammar should be learned through practice. Sociocultural Theory puts scaffolding and peer dialogue at the top of the list of grammar mediation tools.

 One pedagogical implication is that grammar instruction needs to be integrated with speaking goals, task complexity, and the level of proficiency of the learners. The paper ends by pointing out the gaps in longitudinal studies and the need for more research on teaching grammar in ESP/EMI settings, especially when it comes to speaking tasks that are specific to a discipline.