The Drupal 7 translation system including the internationalization package is a heavy beast and while it mostly gets the job done, it is all but intuitive in use.
For high volume translations it is recommended to use the translation template extractor and translate the strings externally. For small corrections however, it is often much more convenient to use the translation interface (admin/config/regional/translate/translate).
The Honeypot module is a great captcha alternative, as it keeps spam bots from submitting content while also saving your site visitors from having to type in mundane character combinations.
Configured properly it will prevent the majority of bots from submitting forms on your site including registration forms, contact forms, comment forms, content forms... any drupal forms.