# What pattern will match accented letters in a regular expression?

How should I modify the following such that the accented letter É is matched and the expression returns True?

StringMatchQ["Éta", RegularExpression["[a-zA-Z]+"]]

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Somewhat related: How to remove accents from text? –  Mr.Wizard Jan 16 '13 at 8:46

StringMatchQ["Éta", RegularExpression["[[:alpha:]]+"]]

On the Documentation page for RegularExpression I see only listing of named classes of characters: alnum, alpha, ascii, blank, cntrl, digit, graph, lower, print, punct, space, upper, word, xdigit. Some of them have self-explanatory names like ascii, digit etc. but some (like alpha) have not obvious meanings. Where can I learn about them? –  Alexey Popkov Jan 16 '13 at 10:36