TOPIC: Change setting 'Only registered users can write ..

I would like to change the Basic Settings which displays the text: 'Only registered users can write comments.' Could you advise how this can be achieved?

This text should be in the language file:
language/en-GB/en-GB.com_comment.ini

You can use language overrides to change it for example directly from the joomla 2.5 backend.
Or you could just directly edit the string.

Regards,
Daniel