Friendica is a community project, and people around the world have started to create and collect resources in other languages. If you know of any sites bundling such efforts, please drop us a line.
Friendica has a chat plugin to enable Facebook-style chat in your browser. However, you may additionally or alternatively wish to use native XMPP clients for their flexibility. For instance, these will let you connect to friends on your mobile device, enable use of more than one XMPP account simultaneously (e.g. by adding a XMPP/Jabber chat account) or facilitate audio and video chats.
Invest 20 minutes to follow the steps on this page, and you’ll be up and running. (Note: jump to Step 2 if you already have an XMPP account - which is the case if the chat plugin is already working for you.)
1) Get an account
First, get yourself an XMPP (also known as “Jabber”) account somewhere - you'll need this for standard browser-based chat in Friendica, too. Just search the web for a service. Free XMPP servers are about as common as pizza parlors. Choose one and sign up. Or install your own XMPP server if you’re a tech-savvy person and have a suitable hosting deal. If you’re a member of someone else’s Friendica site, it’s also possible that your admin will have an XMPP server you can use.
2) Get some software
Next, install an XMPP client on your computer (and another on your mobile device, if you so wish). For instance, we can recommend Pidgin or Jitsi. Download the software of your choice and configure it with your new XMPP account. Consult the appropriate documentation for the software if necessary, but most things will be self-explanatory.
3) Include your Friendica contacts
But if you haven't been using Friendica's browser-chat plugin up to now, you possibly don't have any chat contacts from Friendica yet.... so we’re going to change that right now.
Close down your client for a while to avoid interference. Activate the chat plugin in Friendica itself and configure it to use your personal XMPP account - not the Facebook one. Check the boxes to Approve subscription requests from Friendica contacts automatically and to Subscribe to Friendica contacts automatically . Give the plugin 15 to 30 minutes, and it will automatically add chat connections for those of your Friendica contacts who are also using it (and have enabled auto-approval). These will be now available to you when you use an XMPP client, too. If you want, you can rename them with the client - and the change will carry over to the plugin. So if you have more than one Thomas and it's confusing you, simply add second names.
So now, you can use your XMPP client with two accounts - your generic, personal one (which handles all your Friendica and other contacts) . They can be activated individually or both together, depending on your preference.
4) The rest of the world…
… needs to learn about your XMPP address the old-fashioned way. You might be mailing it to people or writing them a personal message (if they’re on Diaspora, for instance). But this is hardly a complex issue, so we’ll leave you to handle that one for yourself.
5) ... just one glitch
Running the plugin (for browser-chat) and a native XMPP client simultaneously doesn't work very well - so use one or the other at any given time. Native clients interfere with the way the plugin functions - they generally take precedence. If you run a native client and the plugin at the same time, messages and contact requests will normally not reach the plugin, but will appear in the client. Frustratingly perhaps, this will also happen if you leave a client running at home and then expect to be able to use the plugin in an internet cafe or at work. In such cases, only a mobile client on a cellphone (for example) will give you unhampered access to XMPP communication, especially incoming messages.
(If you feel up to some advanced configuration, you can change this behaviour by looking into client priorities. See here: http://blog.roobix.net/2010/02/jabber-xmpp-resources-and-priorities.html.)
One additional piece of advice here: If your preference is to use a native client, you should occasionally activate the plugin to pull updated XMPP contact details from your Friendica friends. The process is automatic. Once it has happened, the new contact details will be available in your native client, too.