Wordpress is used All over the world, As developer you may need to provide your plugin/theme to diffrent languages speaking users, It will be good idea if you create your theme/plugin translation ready.
Wordpress uses gettext libraries for translation
POT stands for “Portable Object Template,” and a POT file (aka .po file) is basically a list of all the English-language text found within the files of a localized WordPress theme.
Once you have the POT file, you’ll need to open it in a program like POEdit, and translate the English language into your preferred language. When complete, you’ll want to save the file twice, as two separate files – a .po file and a .mo file. When you save the files, you must name them according to your language code.
If your theme does not already include it, you’ll need to add the following line to the very top of your functions.php file (just after the opening <?php tag):
Notice “text_domain” above – it’s called the text domain name. You can use any name you want, but you should use the same name that’s used throughout the theme in the gettext function.
You may want to define a constant for your text domain later on it will be hepful in your translation, check example below
// Define Text domain consant define( 'MY_THEME_TEXT_DOMAIN', 'text-domain' ); //load text domain with constant load_theme_textdomain( MY_THEME_TEXT_DOMAIN ); //User Constants in gettext functions _e( 'Hello World',MY_THEME_TEXT_DOMAIN );
There are four main gettext functions
__()Basic funcion that will returs trasnlated text.
_e()It has same function as
__()but it echos the output.
_n()Checks for possible pural string
_x()Useful for when the translation of the word depends on the context.
Both function are basic function for translation, lets check out example for each
echo __( 'Hello World', 'text-domain' ); _e( 'Hello World', 'text-domain' );
Both functions worked same way except
__() returns string and
_e() echos it.
What if we have php variable in string, lets say we want to display color
$color=the_color(); _e('the sky is $color', 'text-domain')
Above example wont work because it will try to find
the sky is blue which it wont be able to find, instead we can do like followings
echo __('the sky is ', 'text-domain'). $color;
printf( __( 'the skye is %s', 'text-domain' ), $color ); //OR echo sprintf( __( 'the skye is %s', 'text-domain' ), $color );
_n() function is used to parse pural string, you can use this function when your output is dependent.
Spam deletion, What if we delete only one spam? The output will be: “We deleted 1 spam messages.”, which is definitely not correct English, and would certainly be incorrect for many other languages as well.
printf( _n( 'We deleted one spam message.', 'We deleted %d spam messages.', $count, 'text-domain' ), $count );
So if we deleted one spam message it will show
We deleted one spam message.
if it has more than one the it will show
We deleted 10 spam messages.
Sometimes a single term is used in several contexts. Although it is one and the same word in English, it may need to be translated differently in some languages. For example, the word “Post” can be used both as a verb (“Click here to post your comment”) and as a noun (“Edit this post”).
In such cases, the
_x() function should be used. It is similar to
__(), but it has an additional second argument.
echo _x( 'post link' , 'A link to the post', 'text-doamin' ); _ex( 'post link' , 'Submit a link', 'text-domain' );
the other functio are mostly puporse dependent or hybrid
_nx()A hybrid of
_x(). It supports contexts and plurals.
_nx( $single, $plural, $number, $context, $domain );
esc_attr_x()Retrieves the translation of
$textin a gettext context, and escapes it for safe use in an attribute
esc_attr_x( $text, $context, $domain );
esc_html_x()Retrieves the translation of $text in a gettext context, and escapes it for safe use in HTML.
esc_html_x( $text, $context, $domain );
Finally, if you haven’t done so already, you’ll need to make sure your wp-config.php file matches your language files. For example, if you’re using a French translation, you’ll need to add the fr_FR.po and fr_FR.mo files to your theme folder, then set your language in wp-config.php, like this:
define ('WPLANG', 'fr_FR');
By the way, your wp-config.php file is located in the main directory where all your core WordPress files are located.
Save your wp-config.php file, upload it to your WordPress installation, and you are ready to go.
**Refer for more details: **
Wordpress : http://codex.wordpress.org/I18n_for_WordPress_Developers
Make Wordpress : https://make.wordpress.org/polyglots/handbook/translating/basics/
Code Tutplus : http://code.tutsplus.com/tutorials/translating-your-theme–wp-25014