a gift for my japanese teacher

hello,

For the past 4 months i've been studing japanese at Berlitz.
I would like to know if it is customary to bring a gift to the teacher when you finish studing?

Thank you!

Did you ask a Japanese custom?
If so, I think your question is highly connected with Japanese culture, so-called groupism.
Usually we don't bring a gift to the teacher individually. We brought a gift to the teacher with our classmates group.
I don't know about the circumstance of language school. But if your school is similar to usual schools of Japan that I graduated I suppose it is better for you to consult with your classmates.

No, it's not customary. Students are not "expected" to give gifts to the teacher(s) at the end of the course, if that's what you are asking.

Of course, if your teacher has gone out of her/his way to help you in addition to the regular classes, for example, to help you pass a language proficiency test or something like that, you are free to express your appreciation by giving a small gift or whatsoever, but it is not "expected."

The "group" thing in the above post applies more to "formal" schools, rather than to training school including language schools. In formal schools (primary, secondary, or colleges) where students have "homerooms" and share a sense of "graduating together" or "growing together" because they are almost always of the same age, then I think it happens more often that the students pitch in together to give some gift to the homeroom teacher, to celebrate their graduation as well as to say thank you and goodbye to the teacher.