In Windows, click on Start | Control Panel | Regional & Language
Options | Languages | Details | Settings. What is the default
input language?
Open a Word document in which this problem occurs. Press Ctrl+A
to select all of the text. Click on Tools | Language | Set
Language | <choose your language> | uncheck the "Detect language
automatically" and "Do not check spelling or grammar" boxes |
Default | OK. This change will affect the current document and
all new documents you create from this point forward. You will
have to make this change individually in your existing documents.
Is Adobe Acrobat 7.0 installed on the computer? If yes, then the
Acrobat 7.0 Create Adobe PDF toolbar add-in for Word prevents
Word from automatically saving changes to the normal.dot template
(which is where some language settings are stored). See
http://www.adobe.com/support/techdocs/331259.html for several
solutions to the problem.