The meeting chair should begin by recognizing the language diversity in the session. This may seem to increase repetition and redundant material but it helps those whose language skills need it. Present your key points in short manageable chunks and in writing. Provide an overview of your presentation in writing on a handout and transparency. Say where you are on your overview as you go though your presentation.
Key questions help to focus the listeners attention.
Aims and objectives are often hard to translate. Try to provide key ideas in a second language. Alta Vista offers a translation service which is often adequate for phrases or key ideas. Pictures and diagrams can help you explain your points. Avoid metaphors, colloquialisms and figurative speech.