Possible Duplicate:
What is the distinction between “role” and “rôle” [with a circumflex]?
What is the significance of the “ô” character in “rôle” in this work?
What is the standard rule for using or not using hyphen and diaeresis on the words like reelect , reexamine, and cooperate?
“Whereäs” as an alternative spelling of “whereas”
In an English science book written by an American, I saw some questionable spellings:
rôle, with a circumflex accent (^) over the o;
coïncidence, with a diaeresis (¨) over the first i but not the second.
Can anyone explain this? I am not a native speaker and don’t understand this culture.