No, it demonstrates I need to be more explicit for some people.

I did not say isAlpha is ASCII-only, I said it was *created* in an ASCII-only time when "isAlpha" was (the Haskell version of) the common name for the operation.  When the Char type became a Unicode codepoint instead of an ASCII character, isAlpha would naturally have been widened to match *and* the corresponding Unicode standard name was imported.  Leaving it as is would have introduced bugs (of the sort that the GHC I/O subsystem had until ghc 6.12 or thenabouts, when it was finally made to use UTF8 instead of "ASCII"/ISO 8859-1).