Create file
data\functions\special\characters.mcfunction
withsay ÄÖÜẞäöüßêéè
use command
/function special:characters
Chat:*
[@] ???????????
*my first try worked correctly but after I changed from editing .mcfunction with notpad++ to windows editor the special characters broke. After that everything I tryed couldn'd fix it (new world; new function with notpad++; use /reload; don't use /reload;...)
Cannot confirm but just don't use Windows Editor.
For me it looks like it places a BOM character in front and therefor prevents the function from loading at all.
Just use something like Notepad++ and set the encoding to UTF-8 without BOM.