If you see it come up in Spanish, can you try to view the source of the page and search for the all.js file. This file is Facebook javascript library. In the path to the file is the language JFBConnect has detected your site is in, and should be something like:
//connect.facebook.net/en_GB/all.js
en_GB = English, es_ES (I think) is one of the Spanish variations. If that's wrong, that will help narrow it down. If not, can you post a page that does this and we'll refresh to try to figure out the cause.
Never heard of this. It's also possible that Facebook is just on the fritz, which happens. Is there any pattern to when it's right vs wrong?
Like Button Language changes sometimes
