This method allows you to have your WordPress installation display in ONE non-English language.
For multiple languages, please use the WPML plugin.
First, configure WordPress to be displayed in your language Obtain the localization files for WordPress by going to http://codex.wordpress.org/WordPress_in_Your_Language and download either a completely translated WordPress package, or just the localization files (.mo and .po files).
Locate the localization files They are named .mo and .po. If you downloaded a translated WordPress package, they are located in /wp-content/languages/.
Copy these files to wp-content/languages/. Open your wp-config.php file and find the line containing: define(‘WPLANG’, ”); And replace it with (this example is for French): define(‘WPLANG’, ‘fr_FR’); Remember to replace “fr_FR” with your language code.
Download and install Poedit, this is needed to generate the localization files Run Poedit Go to File > New catalog from POT file and open the plugin’s language template file located in /wp-content/themes/alice/languages/
Click OK to confirm the new catalog properties Poedit will prompt you to Save the file. Save it into the same folder as the .pot file and name it (this example is for French; replace “fr” with your language code): fr.po
ow you can translate each item in the catalog. Click Save to save your changes; Poedit will generate a fr.mo file which WordPress uses to load translations
It’s very easy to translate with Loco plugin. Please check here: Loco translate plugin