Mailman supports many languages. The pages here provide information on how to translate Mailman, who the current set of language champions are, and much more information on internationalizing Mailman.
First of all, please join the mailman-i18n mailing list. mailman-i18n is where we discuss any and all i18n (internationalization) issues. Please introduce yourself, so we get to meet you, and to find out what you are going to contribute.
Is your language already supported in Mailman? Please see the list of Languages.
You don't have to be a professional or experienced translator to help with the Mailman translation effort. It's a good opportunity to learn how to handle Open-Source Software translations.
If you are experienced with OSS translations, there are (as always ) some project-specific aspects to the procedure.
So, whether your disk is already stuffed with PO files and working copies, or if you haven't a clue what they are, you're equally welcome. Please see our Mailman i18n howto, to find out how to translate Mailman.
Your experience is also welcome in this wiki. Please add any information you think will be useful. If you already use Mailman, you can give us feedback at any stage on how it works for you, using the English interface, or using the interface in your language. If you haven't used Mailman before, or haven't used it much, the translation procedure gives you a chance to get to know Mailman better, so we welcome your feedback as you do that. Mailman is a very widely-used mailing-list manager in the Open-Source world, so we are particularly dedicated to making it as accessible as possible. If anyone can't use it, for any reason, we want to know why.
You'll notice that we have a tracker (Jira) where we'd like you to submit any bug reports, feature requests, or specific information that can be used to improve Mailman. Please register with it, and get those crucial details flowing in!
In general, this wiki is a great place to collect and organize information that will help people use Mailman more effectively. We hope to expand all the spaces to provide more comprehensive Mailman information, for example, current and user-friendly documentation. Please contribute anything you think will be useful.