Abstract. This study addresses the gap in understanding grammatical errors in English compositions among first-year ABEL (Bachelor of Arts in English Language) students at Pangasinan State University – Urdaneta City Campus during the academic year 2022-2023. The objectives include identifying the demographic profile of the students regarding their mother tongue and attitudes toward English grammar and writing, analyzing the most common grammatical errors using the Surface Strategy Taxonomy, exploring the relationship between errors and profile variables, and determining the causes of these errors. A mixed-method research design was employed, with data collected through a researcher-made questionnaire administered via Google Forms and face-to-face writing compositions about students' experiences during the pandemic. Findings revealed that the majority of respondents (60%) spoke Tagalog as their mother tongue, demonstrating a highly favorable attitude toward English grammar learning (mean score of 3.40) and a moderately favorable attitude toward English writing (mean score of 3.00). The most frequent grammatical error identified was misformation (40.69%), followed by omission (32.19%), addition (25.86%), and misordering (1.27%). Results showed no significant relationship between the errors and demographic profile variables. Semi-structured interviews with ten participants confirmed interlingual interference as a significant factor influencing errors, highlighting challenges transitioning from the student’s mother tongue to English. The findings emphasize the need for targeted grammar instruction to enhance independent learning and student outcomes. Practical recommendations include integrating interactive grammar activities, personalized feedback mechanisms, and mother tongue awareness strategies into ESL instruction to address persistent error patterns effectively.

Keywords: English written compositions; Error analysis; Grammatical errors; Interlingual interference; Surface strategy taxonomy