Note that the directives do not work as the apache documentation says they should.

Test results that lead to Gunnar's change above:

Server = 12.04 (Apache 2.2):

Browswer = no language preference list:

1.) No .htaccess file at all: Result: English
2.) .htaccess with only "LanguagePriority en". Result: English
3.) .htaccess with only "LanguagePriority zh-CN". Result: Chinese
4.) .htaccess with "LanguagePriority zh-CN" and "ForceLanguagePriority Fallback". Result: Chinese
5.) .htaccess with "LanguagePriority en" and "ForceLanguagePriority Fallback". Result: Chinese
6.) .htaccess with only "ForceLanguagePriority Fallback". Result: Chinese
7.) No .htaccess file at all: Result: English (Sanity check)
8.) .htaccess with only "LanguagePriority en". Result: English
9.) .htaccess with only "LanguagePriority zh-CN". Result: Chinese
10.) .htaccess with only "LanguagePriority en". Result: English

11.) .htaccess with only "LanguagePriority de". Result: German
12.) .htaccess with "LanguagePriority de" and "ForceLanguagePriority Fallback". Result: Chinese
13.) .htaccess with "LanguagePriority de" and "ForceLanguagePriority Prefer Fallback". Result: German
14.) .htaccess with "LanguagePriority zz" and "ForceLanguagePriority Prefer Fallback". Result: Chinese
15.) .htaccess with only "ForceLanguagePriority Prefer Fallback". Result: English

Now, .htaccess with "LanguagePriority de" and "ForceLanguagePriority Prefer Fallback":

16.) Language preference French. Result: French
17.) Language preference Afrikaans. Result: German (Note: we do not have this language).
18.) Language preferences en then en-US (my original settings). Result: English

19.) No .htaccess at all and Language preference Afrikaans. Result: English
20.) .htaccess with only "LanguagePriority de" and Language preference Afrikaans. Result: German
21.) .htaccess with "LanguagePriority de" and "ForceLanguagePriority Prefer" and Language preference Afrikaans. Result: Firefox doesn't know what to do and asks me. Click O.K. to open with firefox and get a mess, albeit an English mess.
22.) .htaccess with "LanguagePriority de" and "ForceLanguagePriority Prefer Fallback" and Language preference Afrikaans. Result: German


Server = 14.04 (Apache 2.4):

Browswer = no language preference list:

1.) No .htaccess file at all: Result: English
2.) .htaccess with only "LanguagePriority de". Result: German
3.) .htaccess with "LanguagePriority de" and "ForceLanguagePriority Fallback". Result: Chinese
4.) .htaccess with only "ForceLanguagePriority Fallback". Result: Chinese
5.) .htaccess with "LanguagePriority zz" and "ForceLanguagePriority Fallback". Result: Chinese
6.) .htaccess with "LanguagePriority zz" and "ForceLanguagePriority Prefer Fallback". Result: Chinese
7.) .htaccess with only "ForceLanguagePriority Prefer Fallback". Result: English

Now, .htaccess with "LanguagePriority de" and "ForceLanguagePriority Prefer Fallback":

8.) Language preference French. Result: French
9.) Language preference Afrikaans. Result: German (Note: we do not have this language).
10.) No .htaccess at all and Language preference Afrikaans. Result: English
11.) .htaccess with only "LanguagePriority de" and Language preference Afrikaans. Result: German
12.) .htaccess with "LanguagePriority de" and "ForceLanguagePriority Prefer" and Language preference Afrikaans. Result: Firefox doesn't know what to do and asks me. Click O.K. to open with firefox and get a mess, albeit an English mess.
13.) .htaccess with "LanguagePriority de" and "ForceLanguagePriority Prefer Fallback" and Language preference Afrikaans. Result: German