To prevent users from inputting any other characters other than French and English, you can do the following for questions that support Logic:Question validation equation (like Short Text). Also, be sure to add a validation message (separate English and French) to explain what input is allowed.
This is the expression you need to use:
regexMatch("/^[a-zA-ZÀÂÉÊÈËÌÏÎÔÙÛÇÆŒàâéêèëìïîôùûçæœ '-]{3,100}$/",html_entity_decode(self.NAOK))
Note: The {3,100} ensures there are at least 3 characters, and a maximum of 100