Portuguese class

I attend a portuguese class which is held in a cafe every Monday night.
We usually practice reading, grammar, and a bit of conversation.
Basically there is a native Brazilian teacher, but the Brazilian teacher is not always the same person.

[This sentence is ok, but it will sound more natural is split it into two sentences. For example: We are taught by a native Brazilian teacher. However, we do not have the same (Brazilian) teacher every week.]
One of the teachers allows us to speak in Japanese, but the other always tells us not to speak in Japanese. [This sentence will sound more natural if you use less word repetition. For example: Some of our teachers allow us to speak in Japanese, others do not.]
I know it's better to have strict teacher for me to learn, but I am always relieved when the teacher is not strict one.

Your English is very good! Keep up the good work. ^_^