you can record voice with any recording software that is available to you. I use Audacity, which is open source. Just put the audio files in the /alfredo/soundfiles/ directory, together with their corresponding amplitude files (see "Generating the amplitude files - the free way" in Customization) and Alfredo'll do the rest.

it should be sufficient for a salesbot, a FAQbot, a receptionist bot, a bot to show visitors around your site, a greeting bot, an inventory bot, a customer support bot, a store manager bot, a software assistant bot... But i'll certainly keep your suggestion in mind, thanks.