You can do it, but your expression has to contain the actual font names (which may not match exactly the names in your dropdown). So the expression might look like this for “Arial”, “Bookman Old Style”, and “Lucida Console”, for example:
m = effect("LANGUAGE")("Menu").value;
switch(m){
case 1:
font = "ArialMT";
break;
case 2:
font = "BookmanOldStyle";
break;
case 3:
font = "LucidaConsole";
break;
default:
font = "ArialMT";
break;
}
style.setFont(font)