The current study investigates how second language (L2) learners' metacognition integrates practice strategies in self-regulated learning to develop speaking abilities. A Metacognitive Practice Speaking Strategy (MPSS) model was developed to explore specific configurations of metacognitive knowledge, metacognitive strategies, and practice strategies leading to favourable learning outcomes and to identify key contributing factors to proficiency. Semi-structured interviews were conducted with eighteen Taiwanese high school and university students. The findings indicate that high speaking proficiency learners' task knowledge aligns with theories of second language acquisition (SLA). It informs metacognitive strategies to focus on real-world language use through online authentic materials and interaction with real people to gain both fluency and accuracy in speaking. Drawing on these findings, the paper presents a comprehensive list of strategies to assist L2 learners in effectively developing oral communicative competence, along with pedagogical implications. The study turns out to shed light on the integration of areas spanning language learner/learning strategies, SLA, and L2 pedagogies.