I am not sure which ISO standard you follow. I am here below giving clauses in ISO 9001:2000
This comes under general work under documentation.
The following 2 ISO clauses can be attributed to this documentation work:
4.2 - Documentation Requirements
4.2.1 - General (Documentation)
Any type of project fits into ISO standards. For you translating documents from Jap. to English. Hence in your case its not an activity but a project so all clauses would be applicable with some exceptions. For example you will have a
- Work Order
- Acceptance criteria signed-off
- project plan with milestones defined.
- status reporting
- Quality check through Review process before sending the deliverables