Asia-Pacific Forum on Science Learning and Teaching, Volume 6, Issue 2, Article 2 (Dec., 2005)
The effect of teaching in native and foreign language on students' conceptual understanding in science courses
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Social awareness of and efforts spent on foreign language teaching have been clearly increasing in Turkey for years. Along with this awareness and effort, language teaching has undergone many fluctuations and dramatic shifts over the years resulting in more emphasis on the need for all students to become competent language learners.

These fluctuations and shifts in foreign language teaching in Turkey have brought about striking changes which have created several problems as well. One of these problems is related to the selection of schools and their program content. In Turkey, after compulsory elementary school, students study hard to get into state or private secondary schools where they have one year preparatory stage and follow an immersion program. They have to take a central exam to be a student there. These schools use English as the medium for instruction for mathematics, sciences and other academic subjects. Other secondary schools which also accept students after this central exam teach academic courses in the native language, Turkish, and teach English as a course for four hours a week. The differences between these two systems, in the course of time, have raised issues such as students' attainments levels in courses like mathematics and science since these students have a central university exam in Turkish. Thus, foreign language teaching has vacillated between the two approaches in the Turkish educational system: teaching academic courses through foreign language and native language (Koksal, 2002; Koksal, 2003).

Never-ending discussions and criticism of the effectiveness of teaching in a foreign language and the methods to be followed call more attention to this problem in Turkey. It is especially salient at the present time because government policy seems to be in favour of abandoning foreign language as a medium for instruction in secondary schools. The main objections against the use of foreign language as the medium for instruction are students' misconceptions in academic subjects and their academic failure. However, studies across the country related to those discussions are inadequate and need further research, as stated by the Ministry of Education, and several universities and experts in Turkey (Baskan, 1978; Demircan, 1988; Ministry of Education; 1990, 1996).

Research done outside Turkey has looked into the effect of teaching academic subjects in foreign languages as well as bilingual education programs covering problems related to psychology, linguistics and exams. Having conducted several studies concerning the effect of foreign language, Cummins (1981a; 1989; 1992) highlights two levels of language proficiency: the Basic Interpersonal Communicative Skills (BICS) and the Cognitive Academic Language Proficiency (CALP). The former (BISC) represents the language of natural, informal conversation, whereas the latter (CALP) is the type of language proficiency needed to read textbooks, participate in dialogue and debate, and provide written tests. In other words, CALP requires both higher levels of language and cognitive processes in order to develop the language proficiency needed for success and achievement in school. Cummins (1982), Chamot (1981) and Shuy (1981) liken the relationship of language proficiency and academic achievement to an iceberg. While CALP, measuring higher levels of skills, is represented below the waterline, BICS, measuring lower levels of skills, is represented above the surface of the water. The studies by Krashen and Biber (1987), Rosenthal (1996) and Spurlin (1995) support the results by Cummins (1981a; 1982) and state that students who have not developed their CALP could be at a disadvantage in studying academic subjects and science in particular because this course requires an in-depth understanding of concepts acquired by reading textbooks, participating in dialogue and debate, and responding to questions in tests. Once again, stressing the difference between CALP and BICS, educational and linguistic theorists (Cummins, 1981a; Krashen, 1982 and Krashen, Long and Scarcella, 1979) explain that foreign language students may become quite proficient in the grammar, vocabulary and sentence structure of the English language, but may lack the necessary cognitive academic language proficiency to learn the subject matter in science courses.

A study by Johnstone and Selepeng (2001) backs up the claims by Cummins (1981b, 1982; Spurlin, 1995; Krashen, 1982). Johnstone and Selepeng (2001) state that students struggling to learn science in a second language lose at least 20 percent of their capacity to reason and understand in the process. This study has implications for countries which teach their students through the medium of a foreign language rather than in native language. Short and Spanos (1989) claim that basic proficiency is not adequate to perform the more demanding tasks required in academic courses since students do not have exposure to, or lack an understanding of the vocabulary and context-specific language.

The effects of bilingual education on academic subjects and its implications have also been investigated. Research on bilingual education programs and academic achievement has shown that bilingual program students made dramatic gains compared to the success of students schooled in second language only. The study by Collier showed that after 4-5 years of instruction, bilingual program students achieved dramatically whereas the English-only group dropped significantly below their grade level (1989, p. 522). Several studies have also shown that bilingualism may be positively associated with cognitive and academic performance (Duncan and De Avila, 1979; Kessler and Quinn, 1980; Bain and Yu, 1980; Swain and Lapkin, 1981).

Studies by Cassels and Johnstone (1983, 1985), Pollnick and Rutherford, (1993) reveal that learning academic courses through the medium of English poses problems for students whose mother tongue is not English. The explanations given for these problems are linguistic and psychological. Studies exploring the underlying psychological problems indicate that second language learners are frustrated by failure to see meaning in texts and start to have a tendency toward rote-learning. Therefore, not much is stored in memory since what is learned by rote is easily forgotten. Linguistic effects are a result of one's lack of knowledge of grammar, rules of syntax, as well as meanings of words used in different contexts. Poor knowledge of these rules puts second-language learners at a disadvantage, being less able to see meaning in texts, when compared with first language counterparts who have been exposed to inherent and informal methods of learning their language at an early stage (Howe, 1970; Johnstone and Selepeng, 2001).

The results of the study investigating the effect of language on performance of second language students in science examinations by Bird and Welford (1995) also showed the effect was significant. There were significant differences in performance of modified forms of the questions between British school pupils and pupils for whom English was the second language. The study gave a clear indication that the wording of questions in science examinations was a real influence on the performance of second language students.

The studies mentioned above are consistent with Vygotsky's perspective on development and learning. Vygotsky (1978) proposed that the role of language in the development of understanding can be explained in two ways: First, language accommodates a medium for learning. This means that learning can basically take place in a social context and social interaction is the essence of learning. Second, language is a tool which helps the child to construct a way of thinking. Vygotsky considers that studentsí understanding is formed and social experience is internalized through two-stage transformation: social level (interpsychological) and individual level (intrapsychological). Vygotsky strongly claims that concepts can not be acquired in conscious form without language and a child can not have a conscious understanding of concepts before they are explained in a related context using language (Vygostky, 1978).

In the light of these studies, in this study, the effect of a foreign language, English, as a medium for instruction, on conceptual understanding of "The Energy Unit" in a science course was investigated. The reason why it was chosen is because this unit is related to everyday experiences and also covers abstract concepts. As explained by Pfundt and Duit (2000), how to teach the topic of 'energy' is investigated in many studies because of its nature, containing abstract concepts.

The Ministry of Education and several universities have stated that no research related to the effect of foreign languages on conceptual understanding has yet been conducted in Turkey and the results of these types of studies are needed to inform and identify government policies and education targets. This study is of particular importance because several changes in schools following the immersion program are being planned in the Turkish educational system (Ministry of Education, 1990; 1996).


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