A Cre8asite Forums thread asks how do search engines treat accented words? The question itself was worded as follows;
How do search engines deal with the accents commonly used in Spanish, German and other languages? Do they index them? Do people use them in their query strings?
Timely topic, since Google just recently posted at the Google Webmaster Central blog an entry named How search results may differ based on accented characters and interface languages. In short, like I covered at SEW blog;
A search on Mexico will return results for both "Mexico" and "México" and the same is if a searcher enters in México, Google will return results for both "Mexico" and "México." It is clear that the results differ in ranking order, but what makes that order change - well, to me, it is not clear from the post.
There is also some hints on this topic at the SES Latino Show I covered a few months ago. Two specific sessions of interest on this topic may be SEO & Spanish / Portuguese Language Issues & Translate Or Create: Strategies For Those With English-Language Sites.
Cre8asite Moderator Ruud also explains that "most of these languages have their own keyboard layout." Interesting topic.
Forum discussion at Cre8asite Forums.