This study is field linguistic research that highlights surface structure errors within one eighth-grade class at SMP Negeri 1 Kebumen, assessed using the surface strategy error analysis framework proposed by Dullay. This study aimed to answer the raised question of altered error portrayals and the relationship between their behavior patterns regarding their academic performances and social environment. This study is descriptive qualitative research on a single embedded case study, combining SLA and an ethnographic research approach to analyze the four categories of altered errors and the academic and social portrayal. Findings from this study show that students made fluctuating errors, scoring 682 patterns, with the most committed error in the misformation and regularization of the misformation subcategory. There is a positive correlation of the total error with the academic performance and social environment, where the better the academic performance and social environment the students have, the more sensitive their linguistic abilities will be.
