Many students see algebra as a difficult topic. For second language speakers there might also be difficulties comprehending an algebra task linguistically correct. The authors suggest studying how knowledge in algebra and linguistic registers in mathematics interplay for both newly early arrived immigrants compared to first language speakers. We suggest the tools for such a study to be measuring achievement and solution strategy while varying the text intensity and mathematics register in algebra problems for students with different length of experience of Swedish language in school year 9. We want to discuss design of test instrument and methods for background data collection.