Multi-languages with WordPress

You want to manage different languages in WordPress: here are the solutions.

Localisation

• To translate your WordPress web site in your language (or just to change the displayed messages), I would recommend using the Codestyling Localization plugin: it's really simple to use ! Still the template must be designed for localisation (most of them are), and you will translate the language. If you have got  a template with the messages already translated in the language you wanted to use, there's nothing to do ... except, changing the displayed language !
• For more information, lookup articles in the WP Codex working w/ core,  WP in your language !
• Note: to change the date format from US English (to whatever you want), you must change wp-includes/locale.php

Multi-Languages

Multi-languages is more complicated than localisation: typically, we want to display the same page with the text in another  language (by clicking on a button) ... like on this very web site (cf. the button Passer en Français on the top right corner).

An alternative solution is to create a different web site, which is in particular interesting when we want different themes for each language. For a presentation of all possible solutions, read a post on holarails.

To manage one web site with many languages in WordPress, a plugin must be added (read the codex for more informations):

• WPML: not free but it's the reference.
• qTranslate: is often quoted ... but it seems it's not maintained any more (in any cases, it doesn't work well with WordPress v. 3.9.1)
• xili-language: my first choice. A good solution, but a little bit complicated to use, not much choice to manage URL according to the language.
• Polylang: in the end, it's the one I chose. It works, it's easy to use and it's well documented.

Notes about Xili installation & uninstall

It's better to instal the 3 plugins: xili-language, xili-tidy-tags, and xili-dictionary !

Before uninstalling, think about checking the box to delete the links between the translations. They will need to be created again in another system ... or you may delete the pages, articles, categories etc in the language you don't use anymore.

Checkout the themes

For Xili as well as Polylang, check that the theme used has no errors. In particular, checkout, if you use a theme child, and you can not save your changes, verify the comment at the top of your style.css is still present and you have not deleted it by minifying it.

Happy translations ! !