Newstube is a WMPL-compatible and multi-language-ready theme. To translate this theme:

• Download and install this tool POEdit
• Open POEdit and load [/newstube/languages/newstube.po]
• Translate the text and save the file
• A file named newstube.mo is created. Save it in /newstube/languages/ folder. Rename it with Code Name of your language. For example, de_DE.mo for German – Deutsche. See language code list here http://codex.wordpress.org/WordPress_in_Your_Language
• For WordPress 4.0 and above, go to Settings > General and choose Site Language
• For WordPress 3.9.2 and below, open [{wordpress root}/wp_config.php] and find this line define(‘WPLANG’, ”);. Change it with your language code, for example define(‘WPLANG’, ‘de_DE’);

The blog also supports RTL – Right To Left languages. If your language is RTL, go to Appearance > Theme Options > General > RTL mode and check Enable RTL