Your role is to comment on the usage of English and/or Swedish during the meeting.
Before the meeting, prepare to explain the purpose of your role and how you will do it (for example what you will be concentrating on). For example, if your Swedish is stronger than your English, you might mention that you will be concentrating on Swedish. Or, you might concentrate on finding exemplary descriptive language or on finding grammatical errors.
Tip: It is useful to point out outstanding use of language, as well as incorrect usage. For example, you might compliment speakers on their use of very descriptive words, or for their success in explaining a complicated concept in everyday words.