The first is to use the “Review” tab on the main ribbon: There are two main ways to set the language of a new document in Microsoft Word.
Luckily, changing the language in Microsoft Word is a quick and simple process. This is vital because even regional variations of English can differ in spelling, which means the automatic spellchecker will miss mistakes if the wrong settings are used. First, though, you’ll need to know how to change the language settings.
The automatic spellchecker in Microsoft Word is far from perfect, but it can be useful for spotting mistakes in your written work. Changing the Language Settings in Microsoft Word