English and Norwegian have been shown to differ somewhat as regards thematic choice, due to the V2 constraint in Norwegian and to different frequency distributions of some constituent types in clause-initial position. Using the Norwegian component of the International Corpus of Learner English, the present study explores the extent to which Norwegian students apply Norwegian patterns in their choice of thematic structure, and to what extent they have acquired the grammatical and stylistic norms in relevant genres of English. A further aim is to identify areas of difficulty for Norwegian advanced learners of English. The learners make rather few grammatical errors with themes, but certain features have a different distribution than in comparable texts by native writers. E.g. clause-initial adverbials are used by Norwegian learners with a frequency more similar to Norwegian than to English patterns. Formal subjects (it/there) are also over-represented, which is almost entirely due to it-extraposition expressing stance. Furthermore, first-person pronouns are overused as theme in clauses which function as subjective stance markers. One conclusion is that the students seem to master the grammatical structures, but not the discourse conventions of argumentative and academic writing in English.