WordPress can be used in many different languages. By default the language installed and active on WP sites is English. You can easily change your installation language by editing your wp-config.php file which is present in your site’s root directory. Remember it may happen that the language you have defined in your wp-config.php file is not installed in your WordPress site. In such case you can download your language files from here and upload them to Your site root -> wp-content -> Languages directory.
You can easily display Twitter’s follow button in your own language using a sidebar widget in your WordPress based website. Twitter Follow Button for WordPress is a free WordPress plugin that allows you to display Twitter Follow button in various languages (English, French, German, Italian, Japanese, Korean, Russian, Spanish, Turkish) easily.