A family of Microsoft word processing software products for creating web, email, and print documents.
It sounds like you inadvertently toggled a different keyboard/language. Look in the notification area... do you see something like FR (or perhaps two other letters)? If so, click on it and choose the desired language.
To keep it from happening again, you can disable the key combination that toggles keyboard/language. Right-click the EN (or whatever you see) and choose Settings. Exactly what you do after that depends on which version of Windows you're using. Explore a bit, however, and you should be able to discover the place where you choose whether and which key combinations switch keyboards/languages.
Herb Tyson Microsoft Word MVP