Plug into Xchat
But there are more than just language plugins available for xchat. There are two encryption plugins I know of: fish and mircryption. I tried both and found both to have (dis-)advantages. fish already can exchange keys, mcps sometimes is quicker to use. However, you can have a secure conversation between a fish and a mircryption user.
A wide variety of plugins can be found trough the xchat.org plugin search.