[...] recognizing that the speaker was foreign[...]
I respectfully disagree. It is not always that easy to recognize the origin of a poster. I myself have been mistaken for a native speaker on this very board more than once. I was even thratened with a ban, under the (false) assumption that I was a well-known Anglo-Canadian troll's dual.
As a general rule, you can recognize foreigners by their better command of grammar and spelling (no offense meant, just pointing out an - admittedly somewhat embarrassing - fact)