Of course I am using styles.
But including the language in a style does not solve the problem. Nor does changing the default proofing language. In a new doc without any text the taskbar show "English". If Dutch is included in the style definition even selecting a text in Dutch in a new doc doesn't change a thing.
I now made two macros and put a button in the quick access toolbar. Unfortunately, I have choosen two squares in a different color but the color isn't shown