Hi Izolda
Being another non-native speaker I would join your words about use of English by presenters. And would like to thank CALMet 2014 facilitators for providing most of their materials with written summaries. This does help. While face-to face teaching relevant hand out might be used to enhance involvement and understanding.
Yes, Izolda, you have pointed out the Certificate!!!
Students work for them to impress parents or friends (and many other stakeholders), teachers - to impress their students )
Larissa