Red Hat Access UI pages only support the English language. Support for Japanese should be enabled.
This problem is also a matter of implementing nice support for i18n and plugins in ManageIQ / CFME -- still to be done.
This bug has been open for more than a year and is assigned to an older release of CloudForms. If you would like to keep this Bugzilla open and if the issue is still present in the latest version of the product, please file a new Bugzilla which will be added and assigned to the latest release of CloudForms.