As Kendo has its roots in the Japanese language and culture, most of the terminology is in Japanese though the instruction in each country is in the mother tongue. The instruction in a Dojo (training place) can for a beginner seem confusing but after a few weeks he finds it a natural part of the training process.
Another advantage is that when all Dojos are using Japanese terms, a Kendoka, while visiting a foreign country, can be able to participate and understand all the Japanese terms and words used in Kendo.
Kendo.com explains some of the Kendo terminology, presented in four categories:
Kendo.com presens “Terminology” in cooperation with Halifax Kendo Club