[Chat censure script] Accented letters

I have this script: https://gist.github.com/Rochet2/575ca8c59be700636695 but it has a problem that is a bit exploitable.

With this script, players won’t be able to type censured words that are in an array. For example, if a player type the word “wow”, the message will be deleted. There is a problem with that because the system doesn’t look for letters like “ò”, “ø”, “ó”, “ô”, etc.

Is there a way to replace those letters to the normal vocal?

I tried

std::replace(checkmsg.begin(), checkmsg.end(), ‘óòöôõøØð’, ‘o’);even one by one:

std::replace(checkmsg.begin(), checkmsg.end(), ‘ó’, ‘o’);
But it doesn’t work, gives compilation errors. Any ideas?