This study explores the underlying causes of underachievement in English language learning among students in secondary schools in Kaziba, Democratic Republic of Congo, during the period from January to June 2023. The investigation was prompted by the persistent observation that, despite completing four years of English instruction, many learners graduate without attaining functional communicative competence. To identify the root causes of this phenomenon and suggest remedial strategies, we conducted a cross-sectional survey involving 484 students across nine strategically selected schools. The selection criteria included socioeconomic background, school infrastructure, teacher remuneration, working conditions, and annual diploma performance. Schools were categorized into «large» «medium» and «small» institutions. After excluding 21 incomplete responses, data from 463 students were analyzed. The research addressed three core questions: (1) What factors hinder students from achieving English language proficiency? (2) How do institutional practices influence opportunities for effective English communication? (3) What interventions can enhance English language outcomes in Kaziba secondary schools? Findings indicate that underachievement is primarily attributed to ineffective pedagogical practices, including outdated teaching methodologies and inadequate instructional materials, compounded by learner-related issues such as low motivation and disengagement. The study concludes with recommendations for curriculum reform, enhanced teacher training, and learner-centered approaches to promote meaningful language acquisition and communicative competence.