Thanks for the help:

• Myatu Improved algorithms and decision errors

• Julian Meisel JC40 lngTXT (german) (JCaptcha40, Joomla15) de-DE.plg_system_captcha.zip ) (by Julian Meisel)
• Eric Mamin jc3 lngTXT (french) (JCaptcha30, Joomla15) fr-FR.plg_system_captcha.zip (edited by Eric Mamin)
• Stefano Zamboni jc3 lngTXT (italian) (JCaptcha30, Joomla15) it-IT.plg_system_captcha.zip (edited by Stefano Zamboni)

http://groups.google.com/group/joomlacaptcha/files

• wicksj JС4 Patch Joomla 1.5 com_mailto
• iNFERNO de-DE.plg_system_captcha.ini iNFERNO
• Myatu Dutch-language-sounds.zip nl-NL.plg_system_captcha.ini
• Airton pt-BR.plg_system_captcha.ini
• ribafs pt-BR.plg_system_captcha.ini (2)

• Ken
• All those mentioned on the Downloads Tab

Also thanks to everyone who is not mentioned here, but whose messages are quickly helped to eliminate mistakes and make improvements.