Thanks for the precise task description. :) Can be done any time, but if you also need the so-called Unstructured element translation (like translation of sidebar and other things on Commons) just ask.

@Nemo_bis, well as to the unstructured element translation, I am not really familiar with it, neither, I think, any other user in the wiki is, so it is unsubstantial whether we have it now. Yes, surely I will ask it being enabled when we need it, thanks. Though, does the thing work fine when the source language is different than English (while the interface still falls back to en and stuff)?

@Base Should we enable Extension:TranslationNotifications too?

Change 281403 had a related patch set uploaded (by Urbanecm):
Enable Translate extension on uawikimedia

https://gerrit.wikimedia.org/r/281403

In T131731#2177060, @Base wrote:

Though, does the thing work fine when the source language is different than English (while the interface still falls back to en and stuff)?

The default translatable page source language is the content language of the wiki and that should work without any problems. Although, it does fall back directly to the source language for missing translations instead of following the fallback chain. Is this what you mean and want?

If you want to have a different source language (other than the wiki's default content language), Special:PageLanguage can be used if it enabled. The status of this is bit difficult to understand from T69223. If it is available, I suggest you change the page source language before marking it for translation. As this feature is not as much tested as general page translation, please do report issues if you see anything odd.

@Urbanecm, oh I always thought that the notifications are part of the Translate extension too. Yes, please enable TranslationNotifications as well.

In T131731#2177405, @Nikerabbit wrote:

The default translatable page source language is the content language of the wiki and that should work without any problems. Although, it does fall back directly to the source language for missing translations instead of following the fallback chain. Is this what you mean and want?

If you want to have a different source language (other than the wiki's default content language), Special:PageLanguage can be used if it enabled. The status of this is bit difficult to understand from T69223. If it is available, I suggest you change the page source language before marking it for translation. As this feature is not as much tested as general page translation, please do report issues if you see anything odd.

@Nikerabbit
It sounds that it indeed is what I mean and want, though my general unfamiliarity with the unstructured element translation blocks me from being certain. I believe the feature could be enabled then, though it won't be used probably for some time in practice.

Yes, it would be nice to have the opportunity to set per-page source language in the wiki sometimes, the schema change looks like not done yet, though. Will that Special page automatically appear when it's done, or it is to be requested then? (just so that I know whether I will have to just wait then, or act after some fashion).

While I am on asking questions I'll add another one if you please. Are there any plans, or if there are what is their status, as to having two pages as the source for translation? Like person marks page in language A for translation. Person translates from A to B. B gets proofread (or marked by some other means, some precise translation flag or whatever). Person now can translate from both A and B. (Just in case: I do know about translation helpers.) Or any other mechanisms. I can think of cases where it would be useful in the wiki in question that's why it's actual for me.

@Base Ok. Thanks.

In T131731#2177500, @Base wrote:

It sounds that it indeed is what I mean and want, though my general unfamiliarity with the unstructured element translation blocks me from being certain. I believe the feature could be enabled then, though it won't be used probably for some time in practice.

I am sorry I probably misunderstood your question. I was talking about page translations in my previous comment. Unstructured element translation is basically an extension of using interface messages in the page content (which means, the messages are always displayed in the interface language of the user, using normal language fallbacks).

Yes, it would be nice to have the opportunity to set per-page source language in the wiki sometimes, the schema change looks like not done yet, though. Will that Special page automatically appear when it's done, or it is to be requested then? (just so that I know whether I will have to just wait then, or act after some fashion).

The situation is unclear. I don't know the answer for this.

Are there any plans, or if there are what is their status, as to having two pages as the source for translation?

Apart from the assistant languages (aka helpers) which you mentioned, there is nothing planned and no task in Phabricator for this. It would be a valid feature request, but not a high priority.

@Base I submited these changes to Gerrit, we must wait until the code will be reviewed by others.

Change 281403 merged by jenkins-bot:
Enable Translate extension on uawikimedia

https://gerrit.wikimedia.org/r/281403