How to define theme translation file?

Question

If I have WordPress installation in English, then I can define my theme translation file in the wp-config.php file with following:

define('WPLANG', 'sv_SE');

But if I have WordPress installed in the local language then there is already WordPress translation file defined there, then how can I define my theme translation file?

Answer 1

It all depends a bit if your current theme already supports localization.

Does your theme's function file contain something like this?

load_theme_textdomain( 'twentytwelve', get_template_directory() . '/languages' );

If not, add it in there. And change twentytwelve to your theme-directory-name.

After that create a directory called languages in the root of your theme a drop your localization file (theme-directory-name-sv_SE.mo) in there.

Answer 2

If you add the following line to your functions.php file:

load_theme_textdomain( 'my_textdomain', get_template_directory( ) . '/languages' );

The language files for your themes will be loaded from that directory (in this case the languages directory in your themes' folder.
In this folder you can put your sv_SE.po file (or another extension if you wish to use other translation software).

More information about translating a WordPress theme can be found in this article from Wptuts+.
More information about load_theme_textdomain() from the Codex pages.