The Idea about a having the brainfile autoupdate is a very good one. There is only one problem I could see in such an endeavor, It might cause your Hal's personality to drasticaly change. It might be for the good or it might be for the worse
The problem is that Hal might learn a differnt language then the user knows and be unalbe to communicate further with each other. His/Her personality could also change from from something your are used too to something that might not be quite favorable.
I'm not saying it wouldn't be an interesting change of events, you would just need to be able to choose the language and personality types you would be willing to acept. Or you would have to use a different brain then your standard if you didn/t want to loose the current way things were.
As to the use of an IRC I don't know about an automated process but what about using a speech to text translator and having it save the IRC file for later intergration with Hal's mememory. It may take some time each time you added the file but it might be one way to answer your question.
