The default text written in our themes in English, but you can change it to your language. We use a standard translation (localization) method called GNU gettext. According to this method you don’t need to translate each message displayed on your website in source code. Instead you can generate your own file with translation of all messages in one place. You can find the instructions on how to translate a theme on the following page: http://codex.wordpress.org/Translating_WordPress. Also you can use plugin “Codestyling Localization” (http://wordpress.org/plugins/codestyling-localization/) to manage and edit translation files.