> IMHO, the Wiki approach seems to be reasonable than a README file. > It will be suitable for adding non-Japanese translations and > non-core developer can join to translate or fix the docs.
I doubt other than developers can translate those README files since the words used in the files chosen to be understandable for those who are familiar with PostgreSQL internals.
You may be surprised by the quality of translations from non-developers findable in a lot of Open source softwares.