Description of problem:

squid's error_default_language directive makes it possible to display error
pages in dozens of different languages. However, many of these pages are only
partially translated, containing a mixture of English with the selected
language.

Version-Release number of selected component (if applicable):
squid-3.1.23-9.el6

Steps to Reproduce:
# echo 'error_default_language zh-tw' >> /etc/squid/squid.conf
# service squid start

When opening http://localhost:3128/ in a web browser, we get this:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following error was encountered while trying to retrieve the URL: /

    不正確的位置

Some aspect of the requested URL is incorrect.

Some possible problems are:

    缺少或不正確的通訊協定宣告（應該是 "http://" 或是類似的開頭）

    缺少欲連結的主機名稱

    不合法的網站連結路徑（缺少 "//"）

    欲連結的主機名稱包含不合法的字元；底線這個字元是不被允許存在的。

Your cache administrator is root.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

For some languages, the whole page is correctly translated (e.g. Latvian,
Ukrainian). For other, the translation is incomplete, such as shown above.
Finally, the translation of this page is missing altogether for Indonesian and
Serbian Cyrillic.

I did not go through every error page for every language available (there is
hundreds of such combinations). I can provide more details on demand.