Developing the skill to form derivatives is a slow incremental process even for native speakers of English, starting in elementary school and continuing through high school. In fact, it appears to be a universally challenging area of the lexicon. Nevertheless, studies have shown that it is one of the most important skills to possess for a learner aiming to enlarge his/her L2 vocabulary and that it therefore may be worth the while for learners spending time on gaining mastery of affixation rules.

In the present investigation, Swedish university students having studied English as an L2 for at least 10 years were asked to take two similarly constructed tests, both of which were frequency-based (both stem and suffix considered) and focusing on the students’ knowledge of productive use of suffixes. The first part of the tests was a gap-filling context-based exercise whereas the second part, digging even further into the students’ vocabulary depth, tested the students’ knowledge of word families. (The results of native speakers of English were used as a point of reference for the test in English.) The students were also asked to evaluate their L1 and L2 knowledge of suffixation. The present study thus aims to address the following research questions:

Considering 1) the frequencies of the stems and suffixes and 2) the meanings of the suffixes and what word classes they form, what 1) quantitative and 2) qualitative knowledge of suffixation do Swedish university students have in English as their L2 as compared to in their L1?