The PHP manual is available not only in various formats, but also in various languages. The text of the manual is first written in English, then teams of people across the world take care of translating it to their native languages. If a translation for a specified function or chapter has not yet been made, the manual's build system falls back to the English version of it.
People involved in the translations start from the XML source code available from http://cvs.php.net/ and from it they translate to their mother language. They do not use the HTML, the plain text, or the PDF version. It is the build system which takes care of the conversions from XML to human readable formats.
Note: If you would like to help translate the documentation to your native language, please get in touch with the translation/documentation team by subscribing to the phpdoc mailing list: send an empty mail to phpdoc-subscribe@lists.php.net. The mailing list address is phpdoc@lists.php.net. State in the message that you are interested in translating the manual to a language and someone will get back to you, helping you start a new language translation or reach the already active documentation team for your language.
At the moment the manual is available, partly or not, in the following languages: Brazilian Portuguese, Chinese (Simplified), Chinese (Hong Kong Cantonese), Chinese (Traditional), Czech, Dutch, Finnish, French, German, Greek, Hebrew, Hungarian, Italian, Japanese, Korean, Polish, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, and Turkish.
They can all be downloaded here: http://www.php.net/docs.php.