I've created a custom captcha. It seems to work with the exception that I've been unable to give it a name in the admin. It appears as a blank item in the list.
I assumed from http://wiki.phpbb.com/Captchas
that if I created the language file with the right name, and put it in the correct location, it would automatically load.
I've named the file correctly, put in the the language/en folder where I see the recaptcha language file. I've also implemented the get_name method for the plugin which returns the key for the language item.
I can only assume the language file is not being loaded, but I can't find the code that does that job to figure out why it's not loading. And I don't see anything in the other captchas to suggest I need to manually load the language file.