The purpose of this study is to explore the variation of immigrant pupils’ skills of Finnish as a second language in the sixth grade. The study also explores how the variables (mother tongue, gender, educational background of the pupils’ parents, the age and reason of moving to Finland and the time lived in Finland) and teaching arrangements such as preparatory stage, lessons in mother tongue and Finnish as a second language influence the pupils’ Finnish language proficiency. In addition, the purpose of this research is to study the link between the language used by the pupil and the level of Finnish.

The study was a mixed methods study, using the approaches of quantitative survey research and qualitative content analysis. The survey group consisted of 219 immigrants in sixth grade. The research material was gathered using Finnish tests prepared by special education teachers and second language teachers. Teachers evaluated their pupils’ speaking and writing skills by using the Common European Framework of Reference for Languages. The pupils also assessed their own language skills in Finnish and mother tongue. In addition, the pupils and their parents answered the questionnaire prepared by researcher

According to the results, over half had satisfactory level of Finnish. Of all the four language modalities, the participants achieved the best results in the dictation and structure and the poorest results in the text comprehension and reading comprehension. Based on teacher assessment, the pupils' oral communication skills were on average equivalent to independent user (B2) and written communication skills corresponded to threshold level (B1). Their grade point average in Finnish language was 7.26 (on a scale 4-10). The duration of the time lived in Finland, the mother tongue, the age and reason of moving to Finland and the educational background of the parents seem to have indicative link to Finnish skills. The longer the pupils had lived in Finland, and the younger they had come to Finland, the better their success in tests. Pupils with refugee status achieved the poorest results, whereas those returning to Finland succeeded the best. The children whose parents had a higher educational background achieved better test results than those of lower educational background Teaching arrangements had a clear link to success in the tests. According to research results, those who had studied one year of preparatory studies achieved better results than those who had only half a year of preparatory studies. Also studying one’s own mother tongue seemed to support the second language acquisition. Those pupils who had received the least amount of instruction in Finnish as a second language succeeded the best in both the language tests and the teachers' evaluations. The language used by the student was linked to the level of Finnish. Those pupils who used both Finnish and their mother tongue with their friends proved to have better language skills in all competence areas. In the cluster analysis, three groups of language level were identified: low, intermediate and advanced skills level.