While researching about Pedro II, Piauí, a little city in Brasil with a rather terse description in the english wikipedia, I wanted to read the portuguese version, but there was no link in the languages section. Only after opening the "more languages box" I finally found the link to to portuguese wikipedia.
So I suggest to add the language that is local to the topic of the article to the first choice of languages. I don't know anything about the technical background, so it might be not so easy. Maybe one could use the geographic coordinates for this.
Maybe it is easier to consider the length of the article in the different languages. The longer the article, the more it will be of interest also for foreign-language readers.