If you're working in more than one language within a document, Microsoft Word can automatically detect each language as you type it.
Note To use this feature, you must first set up your computer to support multilingual editing, and then enable the languages you want to use for editing.
Notes
To turn off automatic language detection in your document, clear the Detect language automatically check box.
To turn off the automatic detection of a particular language, remove it from the list of enabled languages in the Microsoft Office Language Settings tool. Remove the language only if you don't want to use features particular to that language (for example, date formats) in Word and other Microsoft Office programs.