I'm going to take a slightly different perspective than Byron --
For the most part, this is an English site, (see Jeff's response) and so, there are more speakers of English on here. As such, a question in English is more likely to find someone who can both understand the question and provide a useful answer.
If you were on a site that was dominated by a different language, and I've seen discussion sites in Swedish, German, Japanese, Spanish, etc, then asking the question in the language of that site would make the most sense to get the fastest response.
... but then we have to ask if faster is better -- if there was loss of clarity by translating the question, the translated question might be less specific or be misunderstood, and therefore the answers not be useful to the person asking the question.
I personally think you did the right thing by asking in both the language of the local community and your native language.