This study examines how teachers of Swedish as a second language perceive that they work to strengthen L2 pupils’ knowledge of Swedish. It investigates how the teachers say that they work to improve the pupils’ vocabulary and word comprehension, and what they can find problematic when they work with this. The method used for the study is qualitative, in the form of interviews, with the aim of charting the teachers’ opinions and perceptions of what was to be studied. Four teachers were interviewed, and their thoughts are part of the results in the study. Among other things, it was found that vocabulary and word comprehension are important to work with in Swedish as a second language since a large vocabulary and good word comprehension are the foundation for the pupils’ continued learning. The results also show the importance of conversations in the classroom when it comes to vocabulary and word comprehension, and the use of pictures and reading aloud.