Without a native speaker, but...

In spite of a bad weather, there were 5 of us today. Usually, a native speaker join it, however, he seem to have come down with a cold. So today's lesson was without the teacher.

Yes, there were all Japanese. I think the class or lesson which there're only Japanese have 2 aspects.
One of them is that we can ask some subtle questions in Japanese as it's hard to express in English, especially, about grammar.
The class's advanced-course rather than, so that someone can answer or give advise, opinions.
Another is that we intend to speak in Japanese. In fact I felt I talked in Japanese the greater most of the lesson. On top of that, I couldn't come out English my own will...(T T)

Next time (not only the lesson including a native but also the one such as today's) I should talk and talk even if I don't feel myself to be on track...