The language dictionary you have specified on the Thesaurus dialog box is not installed; you cannot look up words of this language. For example, if you have not purchased a separate language pack, you will be able to look up English words only. Do you want to choose a different language dictionary?
Click on Yes to return to the Thesaurus dialog box, then specify the language of the word you want to look up; click on No to close the Thesaurus dialog box and return to your document.