This study investigates the challenges that non-native pre-service English teachers experience in their target language use when they do their practicum in actual language classrooms. This study found that the common difficulties the student teachers encounter related to certain grammatical structures, explaining unknown words to students, modifying language according to students' level, and authenticity of the classroom language. Furthermore, the findings indicated that the language awareness training had a positive impact on the target language use of the pre-service English teachers.