Language fallback to Spanish (es)
It is true that most Basque speakers live in Spain, but it is a fact, also, that most Basque speakers (including those who live in France or elsewhere) learn English and are able to understand English strings. Moreover, the Spanish version will also have some strings untranslated, so a mixture of Basque-English-Spanish would appear — and any user would find that messy and unacceptable. And in the Spanish version there may also be translation errors which the original English version will not have.
So I see no advantage in changing the language fallback from the original English version into the translated Spanish one.
And in the Spanish version there may also be translation errors which the original English version will not have Xabier Armendaritz
This is FUD, but I understand that posture, since there were years ago many errors, indeed. But I (and several others) have been working hard to correct those during the last years.
I suspect (not being a Spaniard) that there are political reasons for not wanting to change the fallback to Spanish, similar to the recent change in Belarusian-language wikis by which the fallback to Russian was removed. I would personally favor not doing any changes in this regard.
"similar to the recent change in Belarusian-language wikis by which the fallback to Russian was removed" That's Ukranian, not Belarusian, see phab:T39314
10% of Basque don't speak spanish but 100% of them studied english as a second language. Besides, I prefere to have as a reference the source language much more than another translated one. Therefore, I thing that matching a small language with his dominant language (spanish/french), it's not a good idea for the development of the small one. -Sator (talk) 23:23, 1 January 2017 (UTC)
Last V sociolinguistic survey page 15.
Thanks, that's useful. You mean the 14,7 % for "Elebidun hartzaileak"? What does the term mean?
Now what makes you think that the people knowing English are more than 85 %?
Even if those numbers where made up numbers (I don't mean they are). I think is more likely for a Basque/French speaking user to be fluent in English than in Spanish, so I agree that Spanish should not be the fallback language.
I'm sorry but it's extremely unlikely that more than 85 % of the inhabitants knows English. The average for Spain is 24 % and for France 39 %.
This is not about inhabitants, but about users. And basque language users don't use Wikimedia projects because they don't know spanish/french, but because they want to use it in Basque. So if something is not in Basque language they will [politically, socially, technically] understand having it in English better than reading it in Spanish/French. If they wanted to have sentences in Spanish they would read in Spanish in first order, as most of them know the language.