It is clear that languages vary in numerous aspects and are considered to be dynamic and evolving entities. It is evident that each language possesses distinct characteristics, and the way it interacts with another language over the extensive process of language acquisition is of great interest to many experts in the subject of Second Language Acquisition. Language learning is a continuous process that involves exposure to various elements. Despite extensive research, the idea of language transfer remains enigmatic as studies have not fully elucidated it. The objective of this study is to identify the errors that arise due to the influence of the first language on the learning of written English by Turkish learners of English as a foreign language in a formal environment. The objective is to examine the linguistic domains impacted by transfer and to analyze the consequences of this transfer on the educational process. The additional objective is to ascertain whether a correlation exists between the rates of error and the levels of proficiency in the second language (L2). The research questions are addressed through the utilization of qualitative and quantitative data analysis approaches. A total of 252 students were included in this study after excluding the 16 non-native Turkish speakers out of the initial 268 participants. The study's findings indicate that negative transfer is seen in both lexical and syntactical language categories. Empirical evidence has demonstrated a strong correlation between certain error kinds and the competence levels of students. Moreover, further specific recommendations have been proposed to enhance the discipline of Second Language Acquisition (SLA). The constraints of this study have also been incorporated.