The present study was conducted during the usual class time within the first semester of 2010-2011 educational year. Two aspects were regarded in this research. The first one was about the vocabulary and knowledge retention, and the second one about the effect of using pure L2or both L2 and L1 in the classroom.
Vocabulary and knowledge retention
In order to reach a conclusion related to the first matter, I tested the students with the help of the vocabulary and knowledge test which I prepared considering the content of the course. The data collection tool (Appendix 1) was applied to the second grade students right after the formal lectures were launched (pre-test) before any of the requested information was taught to the students, and reapplied in the end of the semester (post-test), which was three months later. Randomly selected items (5 out of 24) from the vocabulary part and (12 out of 42) from the knowledge part were asked to the fourth grade students during the interview sessions in the last week of the semester. Each session took no longer than 20 minutes for each student in the pre-test and post-test applications, and 5 to 7 minutes in the interview sessions. The subjects were informed that it was a research about the course, and that the results would not affect their grades, so that they should feel comfortable. They were also discouraged from giving responses that they were not sure about to assure that the data would reflect what is not by chance or luck. The data were gathered and examined separately for the pre-test and post-test sessions, which were applied to the second grade subjects, and results were compared. Following these analyses, the findings were compared to the results that came from the fourth grade subjects to determine about the approximate vocabulary and knowledge retention rate. The findings were presented in percentages, and discussed in the findings part of this article.
L2 and L1 use
In order to reach a conclusion related to the effect of L2 and L1 matter, I randomly divided the second grade students in two classes (35 students in each class). Before the visa exam was done I delivered my lectures both in L2 and L1 to the both classes for a period of five weeks. After the visa exam, I examined the grades of the students and estimated the average score of the two classes. So, before putting my plan into action I had some concrete data about the success level of the students in each class who were treated in the same way by the same lecturer. Having this in hand, I decided to deliver the lectures in pure L2 with one of the classes, and in both L2 and L1 with the other class. For this reason, I preferred to use pure L2 with the class which provided higher average regarding the grades they got from the visa exam. With the other class in which I used both L2 and L1, English was still used most of the time, but I provided explanation in L1 as well whenever I felt that something was not clear, or when as a teacher I saw it in the eyes of the students. With the other class, however, all additional explanation was in English. This procedure took five weeks until the final exam. After the final exam, I again collected and examined the grades of the students and estimated the average score of the two classes in order to make a comparison in relation with the effect of L1 and L2 use in the treatment. In addition to data collection and treatment procedure, the interview session was done one by one and face to face in the office of the researcher. Totally 30 students were interviewed and each interview took approximately 5 to 7 minutes. Additionally, all second grade students were asked whether the Linguistics I course contributed to their personal and/or professional development or not. The findings are discussed in the following part.