I do think that is a great question and probably one we want to revisit after the Postgres 10 release, which is the next one coming up and will require translation. I know translations take time, and with the growing popularity of PostgreSQL it may not behoove us to start translating more of these releases. I would be curious to learn more how much demand there is for more translation.
(CCing to pgsql-www because I'm writing about the website here)
It is not difficult to translate minor release notes – they are usually short. However, I assume that the website needs some changes to deliver our translations better.
It is very hard to reach translations right now: you need 3 clicks and you do need to know where to go (About>Press>Russian). It would be awesome to show translations right on the front page next to the title of release notes in English. And this would naturally increase, like you say, "demand" for translations.
I understand, that such a change is probably too big to be done before releasing version 10. But it would be important motivation, it would increase interest to making good translations – for example, for 9.6, I see only 7 translation https://www.postgresql.org/about/press/. One of the main reasons of such low number is that very few people reach translations and we (press contacts) feel demotivated that we create something that only few people will read.
But maybe it's not that big change and it could be done before 10 ?..
