I think either one is fine. We use a great deal of Japanese in our dojo, and actually don't use either one very much!
Although, aikido began in Japan, I think as time goes on we will see that it is not culture-specific. As a matter of fact, that helps its acceptance and spread because it embodies principles that are desirable in virtually all societies.
As the art continues to evolve, it may well be the U.S. that becomes the dominant country for aikido. I've not been to Japan, but I would guess that there are as many or more excellent instructors in this country, whether of Japanese origin or U.S. birth. I also think the national character of the U.S. which is to question, experiment, innovate may do much more for the future of aikido because of the pressure to fit in and harmonize in Japan. I mean no disrespect, and merely have in mind the model of the electronics industry for example where the ideas for new products started here and the products were built in Japan.
As Dennis Miller says, "But then I could be wrong."
Have an aiki day!