French L&U was the first SE site to use a language other than English as its official/preferred language for questions and answers. According to at least one of the mods over at FL&U, this has lead to higher quality questions being asked. In other words, it has gone a long way to attract experts.
In comments on another question on our own site, it @JoulSauron suggested we might benefit from using Spanish in place of English, as well.
How would the community feel about moving toward Spanish as our preferred language?
Some things to consider:
This is probably necessary to truly attract Spanish-language experts, like the English-language experts we have on EL&U (notice how the majority of good questions on EL&U come from native English speakers).
It will probably reduce our question and answer rate, at least in the short term.
The UI will still be in English for the foreseeable future. SE has talked about doing translations, but to my knowledge, there isn't even a 6-8 week time line yet. This means that even Spanish-language experts who visit will need at least a very basic understanding of English to get around the site.
This would not exclude questions or answers in English--but it would probably mean we'd make a much stronger effort to translate as many posts as possible into Spanish. The finer details can be discussed later if we want to move this direction.