Which of the following languages is NOT one of the six official languages of the UN?

The correct answer is German, as it is not one of the six official languages of the United Nations. The six official languages of the UN are Arabic, Chinese, English, French, Russian, and Spanish. These languages are used in UN meetings and documents to ensure that communication is accessible to representatives from different member states. The inclusion of these specific languages reflects the linguistic diversity of the UN's membership, catering to the most widely spoken languages among its member countries and facilitating effective international diplomacy. Since German is not one of these six languages, it does not fulfill the criteria for an official UN language, differentiating it from the others listed in the question.