You need to do one other thing besides setting the language to Spanish within
Word - that is, activate a Spanish keyboard to allow typing of accented
characters. Here's the sequence:
Settings / Control Panel / Regional & Language / Languages tab / Details / Add
Drop down the input language list and scroll down to the desired version of
Spanish (there are 20, for different countries). Click OK.
Click Language Bar and check Show language bar on the desktop.
The setting in the language bar (or its minimized version in the status bar
at bottom) indicates which keyboard is active for input. Note that the active
keyboard may change as you move between different windows.
The setting within Word, set by Tools / Language, is independent of the
above, and controls which proofing tools are used. Note that the Language
setting within Word is a CHARACTER ATTRIBUTE, just like a font. That is,
various sections of your document can be set to various languages, and if you
have the proofing tools, a mixed-language document will be properly
spell-checked.