To change the proofing language for new documents, select Default. To change the proofing language in Office for Mac, select Tools > Language in Word or another Office application. Editing - To change your editing language for this file in Office for Mac go to Tools > Language, select your. Here's how you can set the languages in Word for Mac 2016: User Interface - The display language for Office for Mac follows the language that your operating system is set to. Click on Tools at the top menu bar and select 'language' fro. In today's tutorial, you will learn how to change language in Word 2019 for macOS.Open Word app.