Second sentence should have said "these are essentially duplicate 
results," not "essential duplicate results."

This is due to the way in which Yahoo! - like all of the major search 
engines - spiders and catalogs the data.  The site-wide search on the 
PHP website is powered by Yahoo!'s search engine.  Of course, as such, 
you can use Yahoo!'s search operators, meta words, etc. (see http://help.yahoo.com/l/us/yahoo/search/basics/basics-04.html for more 
information), but as far as changing the method in which this is handled 
(i.e. - switching from Yahoo!), I'm not so sure it's planned for the 
foreseeable future.

Thanks for considering. I don't know what setup options Yahoo gives you 
for its search tool, but here are two ideas that might be worth a look:

- The Yahoo search is configured for a starting directory of 
php.net/manual. Is this an argument that php.net passes to Yahoo with 
every search query? If so, the argument could be extended to include the 
language code, like php.net/manual/en.

- The Yahoo search tips page you mentioned above includes an option 
"inurl". When I tried this on yahoo.com, I was able to limit the search 
results to English by including inurl:/en/ in my search terms. 
(http://search.yahoo.com/search;_ylt=A0oGkie5aUlKKacARPRXNyoA?
p=class+constants+site%3Aphp.net+inurl%3A%2Fen%2F&y=Search&fr=yfp-t-
501&fr2=sb-top&sao=1) The php.net site interpreted this as a literal 
string when I entered it into the search box there. But if the search 
script on php.net  automatically added this when it sent the query to 
Yahoo, would Yahoo handle it as it does on its own site?

What I don't understand is why the language detection isn't working, we are explicitly asking for the language you provide (falling back to english if none).

I'd rather try to fix the language detection then to muck around with dirty quickfixes by limiting the search range based on path structure.

Hannes, is it possible to log the actual requests to make sure the 
language _IS_ being supplied correctly?

I only suggested a "dirty quickfix" because I was told the functionality 
of the Yahoo engine was beyond your control. If in fact it supports 
language filtering, then yes, it would be good to fix that.

I just noticed that when I perform a search of the online documentation, 
my language code of "en" appears as an argument in the search result 
URL...

http://us2.php.net/results.php?q=test&p=manual&l=en

...and this has no effect on the search results. However, if I change 
the language code in the URL to es, hu, ru ... then the search results 
are correctly filtered by that language. Apparently it is only the 
default language of en that is being ignored.

HHVVBVGFGFGVDFS

Ironically, this was fixed long ago but the bug has reoccurred now that we are using Google.

Can confirm this is still an issue (tested with 'de' and 'en').

(Additonal) Steps to reproduce:

- Navigate to http://php.net/results.php?q=strpos&p=manual&l=en
- Results for 'en' strpos documentation and 'de' strpos documentation will be 
  shown.
- Navigate to http://php.net/results.php?q=strpos&p=manual&l=de
- Results for 'de' strpos documentation and 'en' strpos documentation will be 
  shown.

I think this is caused by the accept-language header of the user's
browser.  It might not be the best idea to use a third party
search at all, though, for privacy reasons.