The usefulness of English is apparent in today's global culture. A crucial talent is the capacity to express oneselfin the second language and modify one's speech to match the various circumstances in order to convey the intended meaning. The study conducted investigates BSED English students' written sociolinguistics ability. In particular, this establishes the students' sociolinguistics competency in terms of their use of language suitable for communicatingintended speech act as well as their linguistic background. This study used a questionnaire-based descriptive-normative survey method to collect the data needed to measure the variable under investigation. The study finds that family background and other social and cultural factors influence students' language proficiency. According to the study, family background and other social and cultural norms present at home, school, and in the community have an impact on students' language proficiency. Findings also demonstrate students’ sociolinguistics proficiency that was above average. This means that even though their answers contain few mistakes, students still manage to express themselves respectfully and clearly, and appropriately given the contexts. Although grammar mistakes were noted, they had no impact on the sentences' intended meaning. However, it may be assumed that developing students' grammar skills is a crucial component of their higher linguistics ability. As a result, this study recommends also examining students' grammatical proficiency as well as language teachers' intervention strategies so that optimal communicative competence of students areguaranteed.