Abstract:
Second language learners try to use the second language in terms of first language‟s point of view. The purpose of this study was to make ESL learners aware of the gravity of mother tongue intrusion and to analyse certain grammatical errors which undergraduates commit due to mother tongue interference. In this study, an analysis was made to identify the impact of L1 on ESL writings of the undergraduates of Sabaragamuwa University, Sri Lanka. The study is mainly based on the qualitative method of data collection. The data collected from subjects‟ responses were analysed, and the findings were derived. The secondary data were gathered from books, magazines and internet. This study proves that due to lack of certain grammar patterns in native language, ESL learners commit grammatical errors. The word order in English is completely different from the word order in Sinhalese and this particular difference leads ESL learners to commit errors. Thinking in Sinhalese and directly translating it into English is another major error which ESL learners often commit. Therefore it is proved that undergraduates in Sri Lanka as second language learners are affected by mother tongue interference.